They are some of the most dreaded words a police officer can hear: “Shoot me!” “Go ahead kill me!” “Just do it!” The tortured pleas often precede an episode of “suicide by cop,” in which a person in mental crisis, sometimes armed with a knife or other weapon, badgers a street cop to fire at them. Of the nearly 1,000 fatal police shootings in the United States every year, experts estimate about 100 of those are suicide by cop.

But police departments don’t have a protocol for dealing with these incidents. Officers typically draw their weapons, repeatedly shout “Drop the knife!” and hope for the best. So a leading police think tank launched a new protocol and training guide for suicide by cop at the annual gathering of the International Association of Chiefs of Police meeting in Chicago this week, and some big-city chiefs are embracing the proposal as a smart way to reduce police shootings.

The protocol from the Police Executive Research Forum, which has nearly every metropolitan police chief as a member, emphasizes officers must first consider their own safety and that of others, and the guidance doesn’t apply if the subject has a gun. But in the vast majority of incidents, the person is unarmed, one new study shows, or has a knife. PERF’s approach calls for officers to not aim their weapon at the person, move a safe distance away and engage them in a conversation rather than shouting commands.

“Pointing a gun at someone and saying, ‘I’m here to save you,’ it kind of has a mixed message,” said Los Angeles Police Chief Michel Moore, who thinks the guidance makes sense. “We should do anything we can to minimize the use of force and maximize the saving of lives.”

New York City Police Commissioner James P. O’Neill said the protocol was “innovative” and noted “we want to try to minimize officer-involved shootings, in part, to minimize the long-term impact they have on an officer’s health and well-being.” He said he would let officers know “there is not an expectation that you do this every time. But when the situation does present itself, and you have the right people to do this, do your best to minimize shootings.”

Police commanders and those who came up with the approach expect some pushback from line officers.

“There may be circumstances in which the officer is able to do some or all of these things,” said Jim Pasco, executive director of the Fraternal Order of Police, referring to the protocol’s directions to de-escalate a situation by not using a weapon or commands. “But the fact of the matter is, when a person has a deadly weapon and is employing life-threatening force of some kind, it is unlikely that all of the incidents are going to be successfully resolved without use of force. You can control yourself, but you can’t control your adversary, totally.”

Officer Josh Hilling, a patrol officer in Glendale, Ohio, who helped draft the PERF protocol, once shot a man who was walking along an interstate highway in central Ohio. The man attacked him with a knife and was later found incompetent to stand trial in a separate case.

“I didn’t have any of this to fall back on,” Hilling said. “All I had in my head was to yell, ‘Drop the knife, drop the knife!’ I yelled it about 100 times, and it doesn’t work. Everybody communicates differently. Sometimes you’ve got to figure out another way to get your message across.”

Moore said the public is unaware of the “millions and billions” of police encounters that start out hot and wind up violence-free, because the occasional violent event gets more attention. A new study published by two psychologists at Cal State Fullerton found the number of potential suicide by cop incidents in Los Angeles rarely resulted in lethal force.

Authors Alejandra Jordan and Nancy R. Panza studied five years of LAPD data on such encounters. The police’s Mental Evaluation Unit has specially trained officers to handle mental health incidents and tracked events in which subjects either verbally declared they wished to be killed by police or acted in an aggressive manner to encourage being shot. The study found 419 such episodes in Los Angeles over five years, from 2010 to 2015.

Of those 419 cases, Los Angeles officers used lethal force only seven times, killing five of the subjects. One officer was injured. “Less-lethal force,” such as stun guns or bean bag projectiles, was used 71 times. No force was used the other 341 times, or 81 percent. Moore said his Mental Evaluation Unit had 70 fully trained officers paired with mental health clinicians ready to respond to such incidents 24 hours a day.

“Our men and women are constantly trying to find ways to de-escalate situations,” Moore said. “The statistics bear that out.”

A ratio of 80 nonfatal outcomes for every suicide by cop was encouraging to Chuck Wexler and Tom Wilson of PERF, who helped create the new protocol. But few departments have the resources of Los Angeles and even that department does not have a formal policy for potential suicide by cop situations. And “after viewing video after video of officer-involved shootings,” Wexler said, “something stuck out at us. There’s no protocol for these situations. All they know is, when team by someone with a knife, they take out their gun and yell to drop it. The way cops are trained now, it becomes a self-fulfilling prophecy.”

So PERF gathered police officials and mental health practitioners from around the country to devise a smarter way to approach suicidal people. The protocol puts significant emphasis on preparing for such a person when possible, including having dispatchers being more aware of suicidal indications and relaying them to responding officers, and connecting the officers with the 911 caller to get more information about the subject before encountering them.

The PERF protocol has three steps. The first is for the officer to ensure their own safety and public safety. If the subject has a gun, the officer should take cover and call for backup. If the subject has a knife, the officer should maintain a safe distance and use a vehicle or other large object to maintain separation. Police have long been trained to establish a 21-foot zone between themselves and a person with a knife, but Wexler and others said officers are quick enough to still unholster their guns and fire even if the subject is closer than 21 feet.

The first step also informs officers to call in a supervisor and other backup, and for Crisis Intervention Team-trained officers to respond if available.

The second step warns that “pointing a gun at a potentially suicidal person will increase his or her anxiety and exacerbate the situation.” It advises officers to consider keeping their guns unholstered and in “low ready” position, or pointed at the ground.

The Police Executive Research Forum launched a new protocol and training guide to reduce "suicide by cop" shootings. This video does not show a real shooting. (Police Executive Research Forum)

PERF notes less-lethal weapons, whether stun guns or pepper spray or other means, often don’t work as desired and can escalate a situation. Electronic control weapons fail to incapacitate a subject about 40 percent of the time, the PERF protocol states. In an episode last month in Hyattsville, Md., police used three stun guns, pepper spray, a flash explosive and bean bags in an attempt to stop a man with two knives, but the man eventually charged officers and was shot dead.

The third step is to communicate and try to make a connection with the subject. People who have decided to kill themselves “are not going to respond to somebody giving commands,” said John Nicoletti, a Denver psychologist who has trained police in crisis intervention and assisted PERF in creating the protocol. “What the officer has to do is figure out a way to establish a relationship with the person. It’s tough.”

Talking to people in crisis is nothing new for police officers. “Law enforcement realizes it’s not just being a cop,” Nicoletti said, “it’s being a psychologist, it’s being a variety of things. We’re seeing more folks who are struggling with mental illness. The more first responders who can be trained in that, the better endings we’re going to get.”

Police officers are also trained to take charge of situations, to be the one in control. The PERF protocol, which further extends its initiative for officers to de-escalate tense situations rather than resolve them with violence, can conflict with the need to be in control.

“I think there will be initial resistance,” said retired Chief Charlie T. Deane of Prince William County, Va., who studied the PERF protocol, “but once it’s carefully considered, it will be accepted as standard practice. This is just, in my view, a refinement of the skillful practices we have for dealing with potentially deadly situations. This will be incorporated into future training, I’ll bet.”