Takoma Park police Lt. Tyrone Collington yelled to the masked bank robber to drop his gun and loosen his grip on the teller’s neck. It’s not worth it, man. Let the girl go, he shouted.

In an instant, as television cameras rolled, the robber slipped on a patch of ice, the hostage broke free, the robber raised his gun and Collington fired.

“I had to muster all of my skills and my courage to save this life,” said Collington, who was the first of six officers to shoot the gunman that morning in a snowy parking lot. “But I also had to take a life.”

There has been an unusual spate of fatal police shootings over the past year in the Washington region — 18 cases in which officers killed suspects in 2011, more than four times as many as in the previous year, when there were four.

Cops shooting bad guys are a mainstay of police television dramas. But in real life, that moment of confrontation is extraordinarily rare. When it does come, the emotional toll can last forever.

Those who kill in the line of duty often have daunting personal and professional hurdles to overcome. They pull the trigger to protect themselves and others, then live in isolation, suspicion and personal sadness as their actions are scrutinized and investigated, often very publicly.

In rare and poignant interviews with The Washington Post, four area police officers who have killed suspects in justified shootings spoke of the torment.

“I still pray for her and her family,” said Prince George’s Lt. Dan Sheffield, who fatally shot a 16-year-old girl who pointed a gun at him during a standoff in 1996.

Some of last year’s police-involved shootings passed with little attention; others captivated the region, such as the Takoma Park case, which was broadcast live as the drama unfolded on Jan. 28, 2011.

Collington was outside the bank with dozens of other officers when he saw the robber, Carlos Rudolfo Espinoza Arcia, walk out with a gun to the teller’s head. Arcia told authorities that he also had a bomb strapped to his chest.

Collington, head of the criminal investigations division, had seen the teller before because he banks at that Capital One branch.

He remembers her pleading: “Please, don’t let me die. I don’t want to die.”

He felt focused and confident, and he told himself that he was going home that night.

“I’m thinking about my family,” said Collington, 45. “I have two kids.”

When the hostage broke free, Arcia raised his gun toward her. Collington and five other officers fired. Arcia was shot 13 times, twice by Collington.

Officers found out later that there was no bomb attached to Arcia’s chest — just a sham made of sponges and duct tape — and that his gun was not loaded.

“Why he didn’t drop the gun, I have no clue,” Collington said, reflecting on the shooting. “Once I got home, those first few nights were sleepless. You’re thinking about the guy’s family, the victim, the investigation you’re facing.”

Life-or-death moment

D.C. Police Chief Cathy L. Lanier said no police officer wants to use deadly force. “It’s very traumatic emotionally for the officers. It’s devastating,” she said.

None of the officers who shot and killed someone in 2011 has been charged with a crime, but even when the shooting is justified, it is difficult to take a life.

About 95 percent of police officers who carry guns will never use a firearm, law enforcement experts say. The ones who do often fire in self-defense and then learn that the gun pointed at them was not real or wasn’t loaded. But there is no way to know in the split second when it counts.

The life-or-death moment when officers shoot someone is so intense that they often say they never heard the gun fire or they didn’t realize they had pulled the trigger more than once. They sometimes feel that time stood still — that a 10-second encounter seemed to last for minutes or longer.

Police don’t like to speak publicly about shootings because of the personal nature of the incidents.

But Collington, Sheffield and the others agreed to talk about the shootings and how the experience affected them. Although each incident was ruled justified, the men say it has had a haunting effect.

“It changed my life,” Sheffield said. “Once you pull the trigger, it’s not over. . . . You don’t start running credits.”

It was a November day in 1996, and Sheffield and other officers were standing outside a Laurel apartment building as a teenager inside was threatening to shoot people. The officers begged the girl to come out.

When 16-year-old Julie Meade finally appeared, she raised what looked like a handgun at Sheffield and the other officers. Sheffield said he felt “helpless.” The officers opened fire, and Meade was killed. Sheffield learned later that the gun was not real.

The shooting was about 15 years ago, but it still weighs on Sheffield. “It’s not supposed to work this way,” he said.

Across the country in 2010, police killed 387 people in justified homicides, according to FBI statistics. That same year, 153 officers were killed in the line of duty by firearms.

Some cases appear to be clear-cut examples of “suicide by police,” in which someone refuses to drop a gun knowing full well that officers will fire.

Others bring widespread outrage, court filings and political blow-back, such as the 2007 death of DeOnte Rawlings. The 14-year-old was pursued and killed by an off-duty D.C. officer who was combing a Southeast neighborhood for his stolen minibike. Rawlings’s family sued the city, and the case was settled out of court last year.

Many, though, are very tense situations in which an officer must make a split-second decision when confronting someone who is willing to kill.

Such was the case involving D.C. Police Sgt. Gerald “GG” Neill. It happened about 17 years ago when Neill was driving near RFK Stadium, heading into work on his day off to fill out timecards for his officers in the gun-recovery unit. Neill talks about it vividly.

Joseph Cooper Jr. flagged Neill down, and the officer stopped to see whether Cooper needed help. When Neill opened his car door, Cooper attacked him, possibly trying to steal the vehicle. The two wrestled in and out of the car in a “life-and-death struggle,” Neill said. Neill was losing the fight and felt forced to fire his weapon to save his life.

“Everything seemed to go real slow,” Neill said. “Only by the grace of God was I able to survive.”

He was angry for months after the incident, wondering why he had been in the wrong place at the wrong time.

“I thought, ‘Why me? Why did I get chosen?’ I was minding my own business trying to do the right thing,” Neill said.

The only people he could talk with about it were his attorney and a psychologist from the department’s employee-assistance program. With everyone else, he just tried to mask the trauma.

“People ask how you’re doing, and you tell them you’re doing fine — but you’re not,” Neill said.

Neill, 59, retired several years ago after 30 years with the department. He now works for D.C. Protective Services, which provides security for city facilities. He said he doesn’t like to talk about the shooting out of respect for the man he killed.

“I empathize with his family. He was a father, a brother, a son,” Neill said. “It’s sad all the way around. It’s tough.”

“I came back to work quickly, which was good,” said Neill, who was not permitted to carry a gun for a year. “The worst thing you can do is sit at home and do nothing.”

It had such a profound effect on his life that he became president of the D.C. police union so he could speak out for officers who found themselves in similar situations.

“You know what they’re going through. You know they’re being isolated,” Neill said. “They’ll say it’s just part of the job, but you know they don’t mean that. You say a little prayer and hope they’ll be okay.”

Someone he knew

Steve Hudson joined the Prince William County police force in 1982. He had been with the police department for seven years — and on the county’s SWAT team for five — before he saw a police officer fire at a suspect.

It wasn’t until years later, Jan. 14, 1996, that Hudson learned how difficult it is. In his case, he killed someone he knew.

It was shortly after 6 p.m. when a 911 call came from a home in Triangle, a house that was familiar to Hudson because it belonged to a friend who was a sheriff’s deputy. Hudson decided to hurry to the scene.

Upon Hudson’s arrival, Jimmy Lloyd, 32, stumbled out of the house, and Hudson recognized him as his friend’s son. He saw that Lloyd was carrying a handgun and an extra magazine of ammunition.

Lloyd fired two shots into the pavement and then walked slowly toward Hudson.

Hudson, now an assistant chief in charge of criminal investigations, keeps a yellowed piece of paper in one of his files. It contains notes of what went through his mind that night, thoughts he wrote down days later because he wanted to show how much of his classroom training and job experience figured into those critical moments.

But Hudson doesn’t need to refer to the paper, as he recounts his reflections as if the shooting happened yesterday: 15 things he thought of in less than 80 seconds.

He didn’t want to negotiate too long with an irrational shooter, because he didn’t want to put other officers at risk. He measured the distance at about 25 yards, a shot he could easily take. He drew an imaginary line in the road — a point at which Hudson’s supervisor would have been dangerously exposed to a shooter. That would be as far as he would let Lloyd go.

Officers with Hudson later reported that he said: “Don’t make me do this. Don’t make me do this.” But Hudson doesn’t remember what he said because he was so focused.

When Lloyd crossed the line, Hudson pulled the trigger on his Glock, killing Lloyd with a bullet through the heart.

“I was afraid, but there had to be a line, and I knew where it was,” Hudson said. “He crossed it. I couldn’t risk him killing me or my guys.”

Hudson rushed up to Lloyd — splayed on his back — and kicked the gun away. He felt himself screaming at him.

“I was angry at him for forcing my hand,” Hudson said. “I didn’t feel bad about the decision, because I knew it was the right thing to do. But it bothered me that I had killed someone. I didn’t want him to die. I felt really bad that he was dead, that his life had to end there that night.”

It turned out that Lloyd was heavily intoxicated. The reason for the 911 call was that Lloyd had been firing the weapon inside the house, where his mother, his wife and two of his children were cowering.

“You do all these things to prepare and train yourself to make the right decisions, and ultimately you have to take a man’s life,” Hudson said.

Hudson felt a responsibility to tell Lloyd’s father what had happened, and there was an emotional encounter between the two men.

“I told him I had to shoot Jimmy and that Jimmy was dead,” Hudson said. “He grabbed me and hugged me and said, ‘God bless you.’ I think he knew I was upset I had to kill him.”

Hudson later went to Internal Affairs as a commander, a job in which he investigated police shootings. And he has lectured recruits during a “Dynamics of Armed Encounters” class, using the notes on his yellowed paper to help explain the thought processes involved in life-or-death situations.

“I tell the officers involved that they will second-guess themselves, they will have dreams, they might get depressed,” Hudson said. “They just have to know that’s normal. Being able to talk to them having been in their shoes, it makes a lot of difference. It’s not easy to kill someone. But I know that if I have to do that, I can do that.”

Staff writers Theola Labbé-DeBose, Mary Pat Flaherty and Dan Morse and staff researcher Meg Smith contributed to this report.