(CNN) The attorney for a St. Louis police officer accused of fatally shooting a colleague called the incident a "tragic accident" and asked the public and police to withhold judgment until all the facts have been presented.

Nathaniel Hendren, 29, is accused of killing Katlyn Alix, 24, on Thursdayat his residence, authorities said. The two allegedly took turns holding a revolver containing one bullet and pulling the trigger.

Hendren has been charged with involuntary manslaughter in the first degree and armed criminal action relating to the death of a fellow police officer.

Attorney Talmage E. Newton IV expressed his condolences to Alix's family and said her death "has unalterably impacted the lives of everyone involved."

Hendren is devastated by Alix's death, Newton said in a statement Tuesday. "We are aware of the rumors, innuendo, and salacious gossip surrounding the accidental death of Officer Katlyn Alix. There is no evidence, nor will there ever be, that this was anything more than a tragic accident."

Scott Rosenblum, a lawyer representing Alix's family, said in a statement that he was hired "to make sure that the investigation is thorough and proper. We will obviously explore if there are any civil remedies that they can pursue."

Alix was off duty when the shooting occurred and Hendren was on duty, according to the probable cause statement supporting the charges.

The statement said Alix, Hendren and Hendren's partner were playing with guns when Hendren produced a revolver. Hendren emptied the bullets from the revolver and put one of the bullets back inside the gun, spun the cylinder and fired the gun pointing away from Alix, the statement said.

The gun did not discharge. Alix took the gun and pulled the trigger while pointing at Hendren, but it did not fire, the statement said. Hendren grabbed the gun back from Alix, pulled the trigger and this time it fired, striking Alix in the chest, the document said.

The third officer at the scene has not been identified. According to the probable cause statement, he advised Alix and Hendren they shouldn't be playing with guns and left the room. He returned after hearing the gunshot.

In response to a request for comment, Jeff Roorda, business manager for the St. Louis Police Officers Association, said the union was "deferring to the accused officer's attorney."

Nathaniel Hendren was taken into custody and booked Monday.

Hendren was taken into custody Monday. A booking photo shows him with a black eye.

St. Louis Circuit Attorney Kimberly M. Gardner said Friday that Hendren could face three to 10 years in prison.

"I will hold people accountable who violate Missouri law regardless of their profession, public status or station in life," she said in a statement. "Today, as much as it saddens my staff and me to file these charges, Katlyn and her family deserve accountability and justice."

Victim leaves behind a husband

In first reporting the shooting, police said the death was accidental and occurred when an unnamed officer "mishandled" a gun while they were sitting in the living room.

According to a police statement, a call for "officer in need of aid" was put out at 12:56 a.m., and the third officer told the dispatcher they were taking Alix to the hospital.

She was pronounced dead shortly after arrival, the statement said.

Gardner said in a statement that the Missouri State Highway Patrol would assist her office in conducting an "independent investigation regarding potential criminal conduct" in connection with the shooting.

The statement notes the circuit attorney's investigation is part of the protocol in a police shooting to ensure transparency. The police department's Force Investigation Unit also is investigating.

Alix had two years of experience on the force, the police department said. She leaves behind a husband, her parents and a sister, among other family members.

Aimee Chadwick, Alix's mother, declined to comment to CNN on Saturday, citing the ongoing investigation. But she spoke to CNN affiliate KMOV on Friday about her daughter's love of the job.

"Even on her days off, she would go visit her friends down there because, like, I guess when you're a police officer, (you have) that close bond with everyone."

Chadwick said her daughter was "one of a kind."

"There will never be another Katie," Chadwick told the TV station. "She was the most generous person, kindest person. If you needed her, she would be there."

St. Louis Metropolitan Police Commissioner John Hayden called Alix "an enthusiastic and energetic young woman with a bright future ahead of her."

The St. Louis police union said it recognized that the public wants to "understand what happened."

"So do we," the union said in a statement. "But for now, we wait; we wonder; and we weep."