The man accused of killing two Palm Springs police officers as they stood outside his door this weekend used an assault rifle with an extended magazine to fire on his victims through a metal security grate, according to authorities.
As the Riverside County District Attorney's Office prepared to announce official charges against John Felix, sheriff's officials Tuesday released new details in the investigation.
Among other findings, authorities said that Felix, 26, was prohibited from owning or possessing firearms because he was a convicted felon.
"There is ongoing investigation into how he got the rifle," said Riverside County Sheriff's Deputy Mike Vasquez.
The department declined to specify the model or caliber of the rifle but described it as an assault rifle. Authorities previously said that Felix was wearing body armor and had high-capacity magazines in his possession when he was arrested.
Felix, an admitted gang member, spent 18 months in state prison after he was convicted of assault with a deadly weapon in 2010. He had been off parole since last year, according to officials.
John Hall, a spokesman for the Riverside district attorney's office, said prosecutors were finalizing details and expected to announce formal charges at a news conference Wednesday morning.
Felix is scheduled to make his first court appearance and be arraigned Thursday. He is expected to be charged with two counts of first-degree murder with the special circumstances of multiple murder and murder of a police officer in the line of duty.
Riverside County Dist. Atty. Michael Hestrin said Sunday that his office would decide whether to pursue the death penalty against Felix.
"I consider the brutal murder of a police officer to be a very heinous crime, so I will leave it at that," he said.
On Tuesday, the Sheriff's Department said the officers who had been killed were responding to a family disturbance at Felix's home in the 2700 block of Cypress Road just after noon Saturday. A family member told officers that Felix was armed, sheriff's officials said in a statement Tuesday.
"Officers spoke to Felix through a metal screen door and instructed him to step outside so they could conduct their investigation," the department said. "Without provocation or warning, Felix fired upon the officers with an assault rifle."
The officers were wearing ballistic vests at the time of the attack, according to the statement.
Felix was arrested after a lengthy standoff.
In 2010, Felix was convicted of assault with a deadly weapon after an initial charge of attempted murder the year before. He admitted to being a member of a criminal gang as part of the sentencing and served 18 months in prison. In 2013, he was accused of resisting arrest by Palm Springs police on the same street where Saturday's shooting occurred. He pleaded guilty to a count of malicious noise.
The Saturday shooting stunned Palm Springs and sparked widespread mourning for the two slain officers.
Lesley Zerebny, 27, had returned to work early to help out after giving birth to her daughter, now 4 months old. She'd been an officer with the Palm Springs Police Department for just 1½ years.
Officer Jose "Gil" Vega, 63, had submitted paperwork for a December retirement after a 35-year career with the department. Vega, a father of eight, wasn't scheduled to work Saturday but had picked up an overtime shift.
Palm Springs Police Chief Bryan Reyes described Zerebny as "a wonderful, young, dedicated female officer that pressed forward every day to make it better for everybody else."
"She gave her all," he said.
Reyes said Vega chose to continue working even when he'd done so for 30 years, the time when many officers retire. This year, the department needed a training officer, and he stepped up, Reyes said.
"Here he is, 35 years in, still pushing a patrol car for our community to make it better," Reyes said.
Vega was the first one at the door, the chief said.
Memorial services for Vega and Zerebny will take place at 11 a.m. Tuesday, Oct. 18, at the Palm Springs Convention Center. Graveside honors for Vega are scheduled immediately after at the Coachella Valley Public Cemetery, in Coachella. Services for Zerebny will be held at a private location open to family members only.
6:45 p.m.: This article was updated with new details on the announcement of formal charges.
1:35 p.m.: This article was updated with comments from the sheriff's department about the weapon used in the slayings.
10:55 a.m.: This article was updated with details on the postponement of Felix's arraignment.