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A St. Louis police officer charged in the fatal shooting of a fellow officer as they played with a revolver loaded with one round made a court appearance via video on Tuesday, with his attorney calling the incident "a tragic accident."

The prosecutor’s office on Friday charged Officer Nathaniel Hendren, 29, with involuntary manslaughter a day after authorities allege he shot Officer Katlyn Alix, 24, with a revolver at Hendren’s home early Thursday.

Hendren, who has been with the department for one year, is also charged with armed criminal action. He made the court appearance through a video conference from jail, according to NBC affiliate KSDK of St. Louis.

St. Louis Police Officer Katlyn Alix was killed in a shooting on Jan. 24, 2019. St. Louis Police Department

"There is no evidence, nor will there ever be, that this was anything more than a tragic accident," Hendren’s attorney, Talmage E. Newton IV, said in a statement to KSDK. "Nate Hendren is devastated by the loss of Katlyn Alix."

Hendren and another officer were on duty when they were at Hendren’s home. Alix was off duty at the time when she arrived at the home, and Hendren and Alix were allegedly “playing with firearms” before she was shot, according to a probable cause statement.

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Hendren "produced a revolver" and allegedly emptied the cylinder of the gun and then put one cartridge back into the cylinder, spun the cylinder and pointed the weapon away and pulled the trigger, and the revolver did not fire.

Alix took the gun and pointed it at Hendren and pulled the trigger and it did not fire, and then Hendren "took the gun back and pointed it at the victim pulled the trigger causing the gun to discharge," according to the probable cause statement. Alix was shot in the chest.

She was rushed to a hospital by the two other officers where she died, officials have said.

Officer Nathaniel Hendren was charged with involuntary manslaughter after shooting St. Louis Police Officer Katlyn Alix in Missouri. St. Louis Metropolitan Police Department

The other on-duty officer who was there told the pair they should not be playing with guns and reminded them that they were police officers, according to the probable cause statement. That officer was uncomfortable and left the room, but before he left the apartment he heard a shot and returned to find Alix shot, according to the document.

Also Tuesday, it was revealed that Circuit Attorney Kim Gardner sent a letter to the police department questioning the investigation and the lack of blood draws being taken. The claims that police were too quick to call the shooting accidental.

The letter dated Monday says that blood draw requests were made but police instead took a breath and urine analysis "in lieu of the more exact blood specimen test," and that they were collected by Internal Affairs.

Gardner said in the letter that the way the tests were done "appears as an obstructionist tactic to prevent us from understanding the state of the officers during the commission of this alleged crime." The letter was published earlier Tuesday by KSDK and was also obtained by NBC News.

The letter also says that "there was probable cause at the scene that drugs or alcohol may be a contributing factor in a potential crime."

A police department spokesperson did not immediately return a request for comment on the letter or the claims. Newton, Hendren’s attorney, did not immediately return to a voice message left after business hours Tuesday evening.

On Monday Hendren was placed on administrative suspension, which is always unpaid, and the other on-duty officer who was there, who has not been identified, was placed on administrative leave, according to KSDK.

Newton said in the statement published by KSDK that people should not spread “rumors, innuendo, and salacious gossip” about the shooting.

“Our thoughts and prayers continue to be with Officer Alix’s family during this difficult time,” Newton said in the statement.