On the laptop, a video of the jail is seen where Tony Chance Ross was held and tased, as his mother, Shelley Ross, watches in Sulphur Springs, Texas. Tony Ross subsequently died. (Ricky Carioti/The Washington Post)

Mathew Ajibade had been acting strangely shortly before Savannah, Ga., police officers arrested him on suspicion of hitting his girlfriend outside a convenience store last New Year’s Day.

Officers said he was combative, so after booking the 21-year-old Wells Fargo bank employee into the Chatham County Detention Center, a sheriff’s deputy Tasered Ajibade’s abdominal area after he was handcuffed with his ankles bound. They left him in an isolation cell and didn’t check on him for at least 90 minutes, in violation of department policy. When they did, he was dead.

Ajibade is one of at least 48 people who have died in the United States since January — about one death a week — in incidents in which police used Tasers, according to a Washington Post examination of scores of police, court and autopsy records.

The link between the use of Tasers and the 48 deaths this year is unclear. At least one of the deaths occurred when an incapacitated person fell and hit his head. Other factors mentioned among the causes of death were excited delirium, methamphetamine or PCP intoxication, hypertensive heart disease, coronary artery disease, and cocaine toxicity. Twelve of the 26 cases in which The Post was able to obtain autopsy reports or cause-of-death information mentioned a Taser along with other factors.

More than half of the 48 suffered from mental illness or had illegal drugs in their system at the time. At least 10 were Tasered while handcuffed or shackled. Only one was female. Nearly 55 percent of the people who died were minorities. The Ajibade case was the only one that resulted in officers being indicted.

A family photo of Tony Chance Ross, 34, who died after being taken into custody. (Family photo)

Deaths after Taser usage by police are relatively rare, accounting for a fraction of the people who die during or after encounters with officers, according to a comprehensive study by the National Institute of Justice. Research shows that when used correctly, the devices are generally safe and prevent injuries to both police officers and civilians. But when Tasers are used excessively or if officers don’t follow department policy or product guidelines, the risk of injury or death can increase, according to company product warnings and police experts.

Tasers are best known for their ability to incapacitate individuals while used in “probe mode,” when they fire two barbs that deliver an electric current along wires, causing the muscles to lock up. When placed against a person’s body in “drive stun” mode, as happened in the Ajibade case, Tasers do not incapacitate but cause localized pain that can be used to control dangerous individuals. Pain compliance, police call it.

At least nine of the 48 cases this year involved individuals who were Tasered in the drive-stun mode.

Taser International has issued product warnings to law enforcement about drive-stunning, noting the need for caution and restraint when using the technique on people with mental illnesses.

“Drive-stun use may not be effective on emotionally disturbed persons or others who may not respond to pain due to a mind-body disconnect,” the company warned in 2013. “Avoid using repeated drive-stuns on such individuals if compliance is not achieved.”

Chatham County Sheriff’s Office policy prohibits deputies from drive-stunning someone who is restrained, according to Sheriff Al St. Lawrence, who said he fired or forced out 16 people after the Ajibade incident.

The deputy who drive-stunned Ajibade, Jason Kenny, was indicted in June along with another deputy and a nurse. Kenny was acquitted last month of manslaughter and assault, but found guilty of cruelty to an inmate by using excessive force. The other deputy was convicted of public records fraud and perjury, and the nurse was convicted of making a false statement to a state agent. Kenny was sentenced to one month in jail and three years’ probation. Neither Kenny nor his attorney, Willie Yancey Jr., returned several phone calls seeking comment.

Mathew Ajibade is one of at least 48 people who have died in the United States since January — about one death a week — in incidents in which police used Tasers, according to a Washington Post examination of scores of police, court and autopsy records. (Family photo)

“There was a culture from top to bottom that they thought they could use the Taser however they wanted,” St. Lawrence said in September in an interview with The Post. “Deputies were using it as punishment, and you can’t use it as a form of punishment. There was just too much use.”

St. Lawrence, 81, died Tuesday after a year-long battle with cancer.

Ajibade, who grew up in Prince George’s County, Md., was bipolar, his family said.

“If someone is restrained and tased repeatedly, that, in my mind, is torture,” said Chris Oladapo, 27, Ajibade’s cousin who persuaded him to move to Savannah in 2012.

An ongoing debate continues across the country over how police use force — particularly deadly force — in the wake of high-profile incidents in cities from coast to coast. Tasers, though, exist as a tool intended to move away from resorting to things such as chokeholds, batons and pepper spray, which was “an archaic way of doing business,” said Steve Tuttle, a spokesman for Taser International.

“We’re proud that we’ve given a tool to the toolbox that provides a safer alternative than using a baton strike that beats somebody senseless,” Tuttle said. “It’s better than spraying an acid in someone’s eyes that’s going to make them suffer and burn for 45 minutes, even after they’ve complied, versus what we call an elegant, more humane and accountable solution.”

Inspired by science fiction

Jack Cover, the physicist who invented the Taser, said the name came from “Tom Swift and His Electric Rifle,” a science-fiction novel he read growing up. Cover, who died in 2009, told The Post in 1976 that he was fascinated by the book’s fictional weapon, which was capable of “stunning people with blue balls of electricity.”

He first began thinking about the device during the 1968 Watts riots. Not long after, he read a Los Angeles Times article “about a man who had harmlessly gotten stuck on an electric cattle fence for three hours,” he said. “The current immobilized his muscles, and I thought, ‘Why not convert that into a hand item?’ ”

Tasers went on sale in 1975 and were classified as firearms. They drew national attention in 1991 when Los Angeles police were videotaped beating Rodney King and shocking him with a Taser that failed to subdue him.

The modern Taser is manufactured by Taser International, a publicly traded company founded in 1993 with sales that exceeded $164 million last year. The devices are in the arsenals of more than 17,000 law enforcement agencies around the country. Tasers are used more than 900 times a day and have prevented death or serious injury more than 135,000 times between 2000 and 2014, the company said.

In “probe mode,” incapacitation occurs when the electricity causes muscles to contract in a cycle that last five seconds, which can be extended if the trigger is held back or pulled again.

“It takes all of your muscles away and you fall,” said Sgt. Garland Prince, who conducts Taser training for the 77-member Wichita County Sheriff’s Office in Texas and “took a hit during training” to see what it felt like.

In the “drive-stun” mode, the Taser provides a painful shock over a small area.

“It does not incapacitate someone,” said Greg Meyer, a retired Los Angeles Police Department captain and nationally known use-of-force expert. “It actually causes them to act out with greater resistance because of the pain. The person will fight you more.”

In 2011, the Police Executive Research Forum, a nonprofit ­policy and research organization, in conjunction with the Justice Department, issued guidelines discouraging the use of drive-stunning as a pain-compliance method and said that this “may have limited effectiveness and, when used repeatedly, may even exacerbate the situation by inducing rage in the subject.”

Tasers have prompted controversy from the beginning, with hundreds of lawsuits filed over two decades against police and the manufacturer. Tasers are largely sold to law enforcement, but the company also sells models designed for private citizens. Those are banned in some states and the District of Columbia.

A National Institute of Justice study in 2011 cautioned that it is difficult to point to Tasers as the “sole or primary reason for death” because of complex circumstances involving victims who had health challenges or were on drugs.

The NIJ study said that “despite widespread use of [Tasers] in law enforcement,” they are “associated with only a small proportion of in-custody deaths,” noting that the risk of death when a Taser is involved in a use of force “is less than 0.25 percent, and it is reasonable to conclude that [Tasers] do not cause or contribute to death in the large majority of those cases.”

The study found that most deaths “associated” with ­the use of conducted-energy devices “involve multiple or prolonged discharges” and concluded that Tasers “are safe when used properly.” The study also found that the risk of an irregular heartbeat from drive-stunning was “exceedingly low” because “the density of the current in the tissue is much lower in this mode.”

Taser has issued detailed product warnings to law enforcement that “repeated, prolonged or continuous” use “may contribute to cumulative exhaustion, stress, cardiac, physiologic, metabolic, respiratory and associated medical risks which could increase the risk of death or serious injury.” The company also warned operators to avoid sensitive areas on the body, including the head, throat and chest area near the heart.

Taser has won the vast majority of the lawsuits related to the use of the Taser by police departments. The company has twice sued medical examiners who tied deaths to its devices, winning a case in Ohio that ended with a trial court ordering autopsy reports and death certificates for three men to be changed and references to Tasers removed.

The company lost a California case in 2008 after a jury found that the company failed to warn police that prolonged exposure to electric shock causes a risk of cardiac arrest. The company was ordered to pay $153,000 in damages and has since strengthened its product warnings.

Taser was also sued in North Carolina after the March 2008 death of Darryl Turner and was accused of failing to warn users of the risks of deploying the devices, particularly near the heart. The 17-year-old grocery clerk was accused of eating food without paying for it and died after being Tasered for 37 continuous seconds in the probe mode, according to court records.

A Charlotte-Mecklenberg Police Department review board found that the decision to deploy the device was within department policy “but the prolonged use of the TASER was not.”

Turner’s family won a $10 million judgment in 2011, which the judge reduced to $5.5 million. An appeals court affirmed the jury’s finding that the company did not provide an adequate warning but vacated the damages awarded and ordered a new trial on that issue. Before the case went back to trial, it was settled last year for a confidential amount, an attorney for the family said.

“Tasers are controversial because you’ve had deaths behind it,” said former Charlotte-Mecklenberg police chief Rodney Monroe, who retired in July. “If you determine someone has mental health issues or is pregnant, the Taser should not be deployed. Or, if you can see that they’re high on drugs, you need to be cautious in using the Taser.”

‘I really hated it for him’

Tony Chance Ross was delusional — had been for the past 14 years. Many of the 15,000 residents of Sulphur Springs, Tex., including police officers, knew about his mental illness. Ross, 34 and unemployed, had been arrested in his home town 21 times since 2002, mostly for public intoxication, records show.

On March 6, police were called after Ross kicked open a door on a ramshackle house on Beckworth Street in the east Texas town, telling the inhabitant that he believed a woman was being raped inside.

When police arrived, the 191-pound Ross was reportedly high on methamphetamine and refused to comply with their orders. “I feared for the safety of myself and others in the area,” one of the officers later said. Two officers wrestled him to the ground as he violently resisted, drive-stunning him five times for a total of 18 seconds.

Authorities put him in an isolation cell at the Hopkins County Jail, where five officers held him down. They attempted to uncuff him and remove his pants. Although handcuffed, Ross continued to fight, kick and struggle, and one of the officers shocked him in probe mode for seven seconds and then drive-stunned him six more times for 28 seconds. That day, he was shocked for a total of 53 seconds over less than 27 minutes, according to a 95-page investigative report by the Texas Ranger Division that was obtained by The Post.

David Klinger, a use-of-force expert at the University of Missouri at St. Louis and a former Los Angeles police officer, questioned why officers had to drive-stun Ross.

“Why didn’t they just leave him handcuffed in a cell?” Klinger said. “It just doesn’t make sense to drive-stun someone who’s already in custody and in a rubber cell.”

The Police Executive Research Forum guidelines caution against Tasering someone for longer than 15 seconds, saying that this could “increase the risk of serious injury or death.”

When jailers checked on Ross about 20 minutes later, he was sprawled face down and unresponsive on the gray rubber floor. A nearby defibrillator was inoperable — it had a bad battery, jail administrator Kevin Lester said. Ross died at a hospital March 8 after his parents removed him from life support.

The autopsy listed the cause of death as “acute methamphetamine intoxication and physical restraint.”

Sulphur Springs Police Chief James “Jay” Sanders, who has been on the force for 27 years and has been chief since August 2014, said his three officers acted properly. A grand jury echoed the sentiment and declined to indict the men.

“I think my guys tried to do the right thing,” Sanders said, adding that none of the officers was disciplined internally. “But it’s affected me.

“I knew Chance and I really hated it for him, but I don’t believe it was anything that we did that caused that.”

Sanders said drive-stunning Ross was better than “hitting him with the old-fashioned” baton.

Shelley Ross said she can’t forgive police for the way they treated her youngest child.

“They could have shown just a little compassion,” Ross said while viewing a video of the Tasering while sitting in her living room. “He wasn’t a dog on the street. They just left him there to die.”

Stopped over a coat

Donald “Dontay” Ivy was walking alone to the corner store to use the ATM, a pilgrimage he made often, mostly at night. He received monthly disability benefits and wanted to get some cash. Ivy didn’t go out like he used to, before he was diagnosed with schizophrenia after graduating from Virginia State University with a business degree. He didn’t trust many people and constantly worried that someone was going to harm him, according to his stepmother.

“I’d see him all the time,” said Abdo Altiri, who owns R & J Grocery & Deli, the corner store Ivy frequented. “He didn’t bother anybody.”

On April 2, two Albany, N.Y., police officers stopped him 34 minutes after midnight. They were on patrol to curb gun violence, Albany Police Chief Brendan Cox said in an interview. Ivy, who was 5 feet 8 inches tall and 274 pounds, “drew their attention,” the chief said.

One of the officers said he “was drawn” to Ivy because he was wearing a “puffer coat” and the officer thought it was too warm for that type of jacket, according to a report by Albany District Attorney P. David Soares. It was 26 degrees that night.

The other officer, a rookie, told authorities that Ivy looked suspicious.

“The way he was walking didn’t seem right,” the rookie later said.

The more-experienced officer ordered Ivy to show his hands, and he complied. They asked him a series of questions.

“He looked suspicious; that’s what they said,” recalled Ivy’s stepmother, Mary Patrick. “They patted him down. He had nothing.”

The officers decided to detain Ivy “for a sec” because he was making them nervous, according to the report. When they tried to handcuff him, Ivy resisted. The veteran officer Tasered him for four seconds in the probe mode, and Ivy ran.

The officers pursued him, and the officer with the Taser continued pulling the trigger — still in probe mode — with no effect. Three officers tackled Ivy. He continued to resist, and another officer hit him with a baton two or three times on the rear of his right thigh. The officer Tasered him again in the probe mode “at least once” and then drive-stunned him twice.

The Taser’s trigger was pulled seven times, although “it is clear that Mr. Ivy was not effectively tasered all seven times,” the report said.

“On the second drive stun, Mr. Ivy yelled ‘OK, OK’ and placed his hands behind his back,” the report said. “Mr. Ivy was then handcuffed.”

After he was handcuffed and shackled, he continued to struggle and kick and was again hit with a baton on the back of the knee. When officers rolled Ivy onto his side, he was not breathing. His handcuffs were removed, and another officer attempted CPR, according to the police report.

Ivy died an hour later at a local hospital, two days after his 39th birthday.

“It was a senseless, senseless death,” Patrick said. “This has brought a lot of heartache and hatred toward the police.”

The forensic pathologist who performed the autopsy said that Ivy “suffered from an underlying condition that made him particularly susceptible to a heart attack brought on by the stress of the incident with police.”

A grand jury declined to indict the officers. Soares, who declined to comment on the case, said in his report that Ivy’s death should prompt a “thorough review” of the police department’s policies for both Tasers and batons as well as its training, particularly when dealing with the mentally ill. Soares said the officers “did not perceive that Ivy suffered from mental illness.”

Cox also declined to discuss details of the case but said the incident has “affected the lives of a lot of people.”

“This was an extremely tragic incident,” Cox said. “Dontay was not a criminal, and even if he was, we don’t want to see anyone die.”

Lengthy struggle turns fatal

The case of Natasha McKenna in Fairfax County, Va., illustrates the complexity of using a Taser in drive-stun and probe mode to subdue the mentally ill.

Admitted to a psychiatric hospital for the first time at 14, her mental health continued to deteriorate over the years. Bipolar disorder. Depression. Schizophrenia.

She had run-ins with people she believed were trying to harm her. She got into a fight in January in Alexandria after entering a stranger’s car and refusing to get out, despite orders from the owner and Fairfax County police. She tried to strangle herself with the seatbelt in that instance, records show. A week later, she walked into a rental car company in Alexandria, screamed at customers, accused employees of attempting to kill her and left. She had an altercation with police and allegedly hit an officer in the face.

During her hospitalization for mental health, McKenna became violent with male staffers and was strapped to a “transfer board” and put in a “quiet room,” records show. After being discharged, she returned to the hospital; a man had attacked her, she said. Authorities arrested her on the outstanding warrant stemming from the earlier altercation with police and took her to jail.

McKenna, 37, who stood 5 feet 4 inches tall, resisted deputies Feb. 3 when they came to transport her from her cell at the Fairfax County jail. Six male deputies on the Sheriff’s Emergency Response Team, a special unit used to control difficult inmates, were deployed in biohazard suits to deal with her. They said she displayed “superhuman strength,” and they struggled with her for “fifteen or twenty minutes” as they handcuffed her and attempted to shackle her and strap her into a restraint chair, according to a prosecutor’s report on the incident.

She “continued kicking, contorting, tensing her body and locking her legs,” the report said.

In an attempt to control her, Lt. Lucas Salzman Tasered her four times, 20 seconds total.

First, he drive-stunned her in the thigh.

“He deployed the Taser in drive stun as a method of obtaining pain compliance in order to get her legs secured into the chair,” the report states.

But that failed to achieve “neuromuscular incapacitation,” and she continued kicking and tensing her legs, the report said. To incapacitate her, the officer attempted to redeploy the Taser in a combination of drive-stun and probe modes, which causes incapacitation by completing an electrical circuit through the body. But that also didn’t work, because the circuit could not be completed.

The third attempt “was more effective and enabled deputies to secure a strap to Ms. McKenna’s leg but they were still unable to secure her leg restraints to the chair.”

After the fourth attempt, McKenna was finally restrained and the struggle ended.

When another deputy asked McKenna, “How you doing? How you doing?” McKenna didn’t respond. They wheeled her to an elevator and to the sally port — the secured entrance to the jail — where Salzman removed the probes from her legs and asked if the nurse could check McKenna’s vital signs.

“Do you have anything?” another lieutenant asked.

“No,” the nurse replied.

The nurse began CPR and McKenna was taken to Inova Fairfax Hospital “unconscious, unresponsive, intubated and ventilated,” records show. She was declared brain dead Feb. 7. The doctor who treated her in the emergency room said she died from “excited delirium, sudden cardiac death.”

Salzman did not return a phone call.

Commonwealth’s Attorney Raymond F. Morrogh concluded in a 51-page report on the incident that police “acted lawfully and reasonably under the circumstances in attempting to restrain and control Ms. McKenna.” Morrogh also said that her death could not be attributed to the Taser.

“Tragically, it was Ms. McKenna’s metabolically unsustainable and protracted resistance to any restraint due to her mental illness and the ensuing excited delirium syndrome that actually caused her death,” he concluded.

The Fairfax County Sheriff’s Office said earlier this year that it had suspended the use of Tasers while it reviews its policy following McKenna’s death.

Morrogh’s report did not satisfy many who felt Fairfax County had been too heavy-handed with a mentally ill woman.

“Tasers should be used in life-threatening situations,” said Pete Earley, a mental health advocate and former Post reporter who lives in Fairfax County. “This Taser was being used because Natasha McKenna was not responding to direct orders. At no time [in the jail video] do you see those deputies in a life-threatening situation.”

Earley said that jail officials escalated the situation by having six deputies in hazmat suits dragging a mentally ill woman from her cell.

“It’s outrageous,” he said. “Having a mental illness shouldn’t be a death sentence, and that’s what this was.”

Alice Crites and Julie Tate contributed to this report.