The device was supposed to deliver a jolt strong enough to stun him so the officers could take him into custody. But the Taser had no effect, police said.
Instead, the LAPD said, the man snatched the stun gun from the officer and shocked her in the leg, leaving her unable to move. Her partner then opened fire, fatally shooting the man, Neil Peter White, in the back of the neck.
White's killing last year illustrates a troubling weakness with a weapon meant to play a key role in the LAPD's efforts to reduce the number of police shootings: Tasers often don't work.
A Times review of department statements and reports found that nearly a quarter of the people shot by on-duty LAPD officers last year — at least eight of 36 — were wounded or killed during encounters in which officers said they tried to use a Taser without success. Among the incidents:
In March, an officer fired a Taser at a homeless man suspected in an assault in downtown L.A.'s skid row. The man spun his arms and kept moving during the violent encounter, which was caught on a bystander's video that drew international attention. An officer tried to stun him again while they struggled on the ground moments before he was fatally shot.
A few months later, an officer shot his Taser during a chase down a South L.A. alley, after the LAPD said a robbery suspect suddenly stopped and turned toward police, a knife in her hand. The Taser had no effect, police said. Instead, the woman moved toward one of the officers and was fatally shot.
In December, two officers tried to use their Tasers on a vandalism suspect during an altercation inside the emergency room at Harbor-UCLA Medical Center. But police said the man continued to fight, throwing a metal stool, jumping on one officer and trying to grab his holstered gun before the suspect was shot and killed.
Other encounters where officers didn't shoot their guns also showed the limitations of the weapon. LAPD officers fired Tasers just over 1,100 times last year, according to a department report published last month. The devices had the desired outcome — causing someone to submit to arrest — only 53% of the time.
"I find that figure very disappointing," said Capt. John McMahon, whose office compiled the report.
Taser spokesman Steve Tuttle defended the stun gun, saying police are trained to understand that they may need to use a Taser multiple times "because the first shot may not work."
Tuttle said it was more important to look at whether using a Taser ultimately helped officers make an arrest, regardless of how many times the device was activated.
It's not always immediately clear why a Taser wasn't effective.
Some people have tugged the metal probes from their bodies, rendering the device useless. Mental illness or drug use can also influence how a person reacts to the shock. Sometimes the fault lies with officers who don't use them properly. LAPD officials are also exploring whether a new Taser model was a factor.
McMahon said the department is taking a close look at each case in hopes of better understanding what happened.
The captain, along with policing experts and the Taser spokesman, stressed the devices still provide officers with an important alternative to using their firearms and have helped reduce injuries to civilians and officers. But officers have noticed the problems, and experts warn that the ongoing concerns could prompt police to go for their guns instead of their Tasers.
The findings come as the LAPD looks to vastly expand the number of Tasers available to officers, part of a broader push by the department and Police Commission to emphasize so-called de-escalation strategies. In September, LAPD brass ordered field officers to carry the devices on their holsters unless they weren't available.
But stories of Taser problems have spread through the LAPD ranks, leaving some officers wondering whether the stun guns will do their job when they're needed.
Officer J.C. Duarte knows from experience. Duarte, who has spent more than three decades with the LAPD, recalled an encounter some 25 years ago, when he pulled the trigger on an older-model Taser, hoping to prevent a physical fight. The Taser didn't work. Duarte grabbed his baton instead.
Duarte said he still carries a Taser because it can help him avoid a fight. When it works, he said, "it works beautifully."
But, he said, the thought of that troublesome Taser decades ago still lingers.
"Whenever I have it, I say, 'I hope that thing works,'" Duarte said. "I've had dreams where I pulled the trigger and nothing happens."
LAPD Chief Charlie Beck said he is concerned by the number of shootings where officers struggled with their Tasers, and he said the department would look for ways to improve the overall effectiveness. But, he cautioned, like any device used by police, Tasers "don't work in all dynamic instances."
"It's a great tool, but is it a magic device that eliminates the need for all other applications of force?" Beck said. "No, absolutely not."
Tasers date to the 1960s, when a NASA physicist thought police needed a weapon for emergencies when a gun could be particularly dangerous, like airplane hijackings. Jack Cover named his stun gun after the hero in a popular science fiction series. (TASER stands for "Thomas A. Swift's electric rifle.")
Tasers can be used in two ways. Officers can fire two electrified darts from several feet away, delivering a sharp shock that freezes someone's muscles and temporarily incapacitates them. They can also use Tasers in "drive-stun mode," where the device is pressed directly against someone's skin and creates pain to gain compliance.
Police agencies across the country have embraced the devices, saying they offer officers more space and time to take someone into custody without having to use their firearms. Charles "Sid" Heal, a retired Los Angeles County sheriff's commander and expert on less-lethal weapons, said any time cops can make an arrest using a Taser instead of a gun, it should be considered a "save" — even if it takes several attempts for the Tasers to do the job.
"We know their shortcomings," Heal said, "but it's better than the alternative."
Heal cautioned, however, that if officers have more problems with their Tasers, they may be less likely to use them and could instead go for their guns more quickly.
"It's going to create a predisposition that you're expecting a Taser failure," Heal said. "'I'm not going to risk my life for a 50% success rate.'"
LAPD officers used Tasers in more encounters in 2015 than in previous years, according to a sweeping use-of-force analysis the department published last month. Officers used Tasers in 519 incidents, up 100 from the year before.
The number of activations also jumped. Officers pulled the triggers on their Tasers 1,101 times in 2015, about 280 more times than the year before, the report said. Last year's effectiveness rate of 53% marked a significant drop compared with recent years, when it ranged from 60% to 65%.
Experts said there are a variety of factors that can influence whether a Taser works as desired. Baggy clothing or sudden movement can rip the wires away. The drive-stun mode may not have the same effect on some people, particularly those who are under the influence of drugs or who are mentally ill. The LAPD's report did not specify how often the device was used in drive-stun mode.
Most of the shootings by LAPD officers last year remain under investigation. Some of those cases, however, have been completed and reviewed by the Police Commission, offering more detail as to why police believe officers had problems using their Tasers.
During the skid row encounter, McMahon said, the officer fired the Taser's probes at Charly Keunang, hitting the man known as Africa in the ideal location: his abdomen and torso. But an autopsy showed the probes never pierced his skin. Instead, McMahon said, Keunang spun and was able to pull the wires from his clothing.
"The spinning motion was able to defeat the objective of the Taser," McMahon said.
Dan Stormer, an attorney representing Keunang's family in their wrongful death lawsuit, was skeptical that the problems with Tasers are so widespread. He said he believed officers blame the devices when explaining later why they fired their guns.
"I think it is often used as an excuse for police officers who become panicked and go to lethal force rather than wait for the Taser," he said.
Earlier in the year, officers went to an Arleta home after a woman called police, warning that her 40-year-old brother, who suffered from schizophrenia, was threatening suicide. The officers found Alvin Pinwatana in a bathroom, police said, covered in blood and holding a butcher knife.
As Pinwatana moved toward police, one officer fired his Taser, according to an internal LAPD report. Another shot his gun, wounding Pinwatana in the shoulder.
Pinwatana fell to the floor, the report said, but began to stand as soon as the Taser stopped. The officer pulled the Taser's trigger a second time. Pinwatana stood and kept moving toward police.
"It's not working correctly," the officer recalled.
The officer ultimately activated the Taser four times before police were able to take Pinwatana into custody, the report said.
McMahon said it's unclear why the Taser didn't work on Pinwatana.
In another case, an officer tried to fire a Taser at a suicidal man who charged police while holding two kitchen knives, but the officer couldn't disengage the safety switch. A second officer then opened fire, fatally shooting the man, according to an LAPD report.
That case, McMahon said, was an example of "operator error." The LAPD did not count the incident as an ineffective use of the Taser because the device was never fired.
The drop in overall effectiveness, McMahon said, also coincided with the department's switch to a newer Taser model. The department's recent force report does not compare the effectiveness of the two models. McMahon said LAPD officials were working with the manufacturer, Arizona-based Taser International, to evaluate the new X26P device and look for any improvements.
Tuttle, the Taser spokesman, said, he had no concerns about the new model. He said the LAPD's numbers were important to have, but "disingenuous."
"It's great to keep track of that … hey, it may take more than one cycle to get that person under control," he said in a phone interview, while zapping a Taser in the background. "But ultimately we would call that success because you didn't have to go to a higher level of force. The Taser accomplished its mission."
McMahon wasn't convinced. "That's something we would rather avoid," he said. "Ideally, a Taser would be effective the first time."