Updated

A grand jury's refusal to indict a former Las Vegas police officer for using an unapproved chokehold in the death of an unarmed man last year drew anguished tears Friday from the dead man's mother and complaints from civil rights groups.

Trinita Farmer said she blames the former officer, Kenneth Christopher Lopera, for the death of her 40-year-old son, Tashii Farmer Brown.

"I want justice for my baby," the mother sobbed. "They say he had an enlarged heart. I don't know anything about that. My baby had a good heart."

Farmer referred to Clark County coroner's findings last year that Brown's death was a homicide resulting from "asphyxia due to police restraint," but that an enlarged heart and methamphetamine in Brown's system were "significant contributing conditions" to his death.

Lopera's legal and union representatives gave the grand jury the results of a defense investigation, including testimony from medical and police use-of-force experts, and a former mixed martial arts fighter.

The goal was to convince grand jurors that cardiac arrest killed Brown, not a chokehold, said Steve Grammas, the union's executive director.

Lopera himself did not testify, said David Roger, attorney for the former officer and the Las Vegas Police Protective Association.

Lopera was dismissed from the police department last September after police said he violated department use-of-force policies.

The officer chased Brown through restricted employee hallways and outside the Venetian resort, where video from the officer's body camera and casino security views showed Lopera using a stun gun on Brown seven times, punching him more than 10 times and putting him in what police supervisors called an unapproved chokehold for 73 seconds.

Brown's death spawned protests and a federal excessive force and wrongful death lawsuit on behalf of Brown's children.

Sheriff Joe Lombardo, elected head of the Las Vegas Metropolitan Police Department, changed policies to stop routine use of neck holds.

The grand jury decision still leaves the prosecutor with several options in a state that moves felony cases from local to state courts either through grand jury action or by a judge's decision after a preliminary hearing.

Clark County District Attorney Steve Wolfson's office could ask for a local judge to hold a preliminary hearing or he could drop the criminal charges. That would let him air the case in a public forum used after police-involved deaths.

Wolfson could refile charges if new information emerges in that non-court venue.

Wolfson has not said how he will proceed.

"I would like for the public to eventually learn all the information and all the evidence," he told The Associated Press.

He plans to meet with Trinita Farmer's lawyer, Andre Lagomarsino, who said he wants a judge to hold a preliminary hearing, or he'll ask the FBI to take over the case.

"We believe it's a civil rights violation," the attorney said. "Trinita Farmer wants Kenneth Lopera prosecuted to the fullest extent of the law."

Roxann McCoy, president of the NAACP in Las Vegas, said the public is entitled to see the evidence that led the grand jury to reject criminal charges.

"I'm very, very curious as to what they saw that we didn't," McCoy said. "I don't know why, when it's a black man, there's always a reason — no matter what we see — that there's something he did to cause his own death."