The man accused of killing a Sacramento police officer Wednesday evening and engaging officers in a nearly eight-hour standoff is facing a murder charge, according to police and jail records.

Adel Sambrano Ramos, 45, surrendered to police just before 2 a.m. Thursday, hours after he allegedly shot Officer Tara O’Sullivan, who was at a home with other officers helping a woman collect her belongings after a reported disturbance, police said.

Ramos continued to fire at officers after O'Sullivan was injured, officials said. O'Sullivan died of her injuries at a hospital.

The officer graduated from the police academy in December. She was partnered with a training officer when she was shot and had been scheduled to go on her own in a couple of weeks, police Deputy Chief Dave Peletta said.

Officer Tara O' Sullivan. Sacramento Police Department / AP

"She was a hero," said Melissa Repa, director of the career center at California State University, Sacramento, where O’Sullivan completed the Law Enforcement Candidate Scholars program and majored in child development. "She’s a role model to so many people."

Sacramento police said Thursday that Ramos was booked on charges relating to the murder of O’Sullivan, and online jail records show a charge of murder as well as a warrant arrest for battery.

A spokesperson for the Sacramento District Attorney’s Office did not immediately respond to an emailed request for comment late Thursday, and it is unclear if Ramos, who is being held without bail, has formally been charged.

It was not clear if had an attorney who could speak on his behalf.

A moment of silence was held Thursday night at a Sacramento police academy graduation ceremony for 56 new recruits.

"We suffered a devastating loss yesterday with the death of Officer Tara O’Sullivan, who was killed in the line of duty," police academy director Lt. Steve Oliveira said.

Adel Sambrano Ramos. Sacramento Police Department / AP

"Yesterday’s tragic events remind us of the potential dangers of this profession, as well as the tremendous commitment and sacrifice law enforcement officers make every day," Oliveira said.

No other officers were reported injured in the shooting and standoff, in which police said the suspect appeared to fire at random. Police have said they think he was shooting with a rifle. Five officers fired during the situation.

Ramos has had several prior criminal cases, including a domestic violence case, according to court records.

Court filings show a warrant was issued for Ramos nine days before the shooting after he failed to appear in court on a November misdemeanor battery charge involving a female minor, the Associated Press reported.

A judge twice granted domestic violence restraining orders against Ramos issued at his wife's request in 2004 and 2007, court records show. In both cases, he was required to give up his guns. The restraining orders later expired.

Sacramento police continue to block off the scene where a police officer was fatally shot in Sacramento, Calif., Thursday, June 20, 2019. Don Thompson / AP

Orlando Ramos, the younger brother of the suspect, told the AP that Adel Ramos is estranged from his family, and Orlando Ramos expressed his condolences to O’Sullivan’s family.

"If he goes to prison for the rest of his life, I could care less," Orlando Ramos told the news agency. "I'm a lot more heartbroken for seeing the pain in my mother and for the police officer and her family than I am for him going to prison."

California Gov. Gavin Newsom ordered flags flown at half-staff.

“Officer O’Sullivan represented the best of what we hope to be as human beings in her selfless service to the community and readiness to help those in need,” the governor said in a statement.