NEW YORK (AP) -- When Kenneth Chamberlain Sr.'s medical alert pendant accidentally went off five years ago, the 68-year-old told police who showed up that he was fine, barred them from entering his apartment and repeatedly asked them to go away.
They didn't. That set off a tense, 90-minute standoff that ended with the mentally ill, former Marine, shot dead.
What lived on is a dispute over whether the black victim was an armed threat when a white officer fired his gun - the question central to a federal civil case set to go to trial this week. Opening statements are scheduled for Wednesday.
The deadly 2011 encounter at Chamberlain's apartment in suburban White Plains - much of it captured on audiotape that will be played for jurors - was a precursor to the national debate over use of force by police in communities of color and in response to calls involving emotionally disturbed people.
Chamberlain's case combines both issues, said his son, Kenneth Chamberlain Jr., whose family filed a $21 million wrongful death lawsuit that went forward after a grand jury declined to indict the shooter.
The son calls his father a victim of "systematic racism" by law enforcement.
If the officers had been confronted with the same situation in a more affluent neighborhood, "It would have been 'Sorry to disturb you,' and they would have been gone," he said.
To bolster that point, lawyers for the family unsuccessfully sought to introduce tape of an officer, later fired, using a racial slur during the confrontation. The officer, Steven Hart, died last year in an auto accident.
The plaintiffs have also accused White Plains' Department of Public Safety of failing to properly train officers in how to deal with emotionally disturbed people.
New York City was confronted with the same criticism last month after a white officer fatally shot a 66-year-old black woman diagnosed with schizophrenia. The woman, Deborah Danners, lunged at the officer with a baseball bat in a bedroom in her Bronx home, according to an initial police account. Mayor Bill de Blasio and police officials called the death avoidable.
In the Chamberlain case, the officers behaved "like a SWAT team," said one of the plaintiff lawyers, Randolph McLaughlin.
"They weren't trained to de-escalate, only to go forward," he said.
Lawyers for Anthony Carelli, the officer who fired the fatal shot, and the city of White Plains did not respond to requests for comment. In court papers, the defense has insisted the shooting was justified, saying Carelli "used deadly force only as a last resort."
The officers have also said they persisted in trying to coax Chamberlain into opening the door so they could make sure he was safe, which the defense says was required by department policy before they could leave.
At the time of the shooting, Chamberlain was living alone and suffering from bipolar disorder, arthritis and respiratory illness, conditions that prompted his family to give him a LifeAid medical alert device in case he needed help.
On Nov. 19, 2011, Chamberlain accidentally set off the alert, prompting police to come to his door. In transcripts of recordings of the encounter captured by a LifeAid help center, he can be heard telling the officers he didn't want them there.
"Go home to your wives and children," he said.
As the officers persisted in trying to coax him into opening the door, Chamberlain sounded more agitated and disoriented, saying at one point that he was in touch with "the President and Vice President Biden."
Police say he poked a knife through a crack in the door, repeated, "honor, honor, honor" and then warned, "First one through the door, I'm gonna kill."
Backup officers, including Carelli, were called in to remove the door. Once inside, they sought to subdue Chamberlain with a stun gun and a bean bag weapon.
In a deposition, Carelli claimed it didn't work, and he watched as the victim came within feet of a sergeant with the knife raised before he fired two rounds.
"He wasn't standing straight up and gingerly walking to (the sergeant)," said the officer, who's expected to testify at trial. "He was charging."
The plaintiffs counter that Chamberlain's health was too fragile for him to put up that kind of fight. They also say ballistic and other evidence shows that Chamberlain was on the floor and helpless when he was shot.
Either way, the victim's son believes his father could see it coming.
"To listen to that audio, it brings tears to my eyes, because I hear the fear," he said. "He believes that they're going to do something to him and that's exactly what happens. They killed him."