'It's devastating': US policewoman killed in deadly game of Russian Roulette

An off-duty police officer has been killed in a deadly game of Russian Roulette - and her colleague has been charged with her manslaughter.

Katlyn Alix, 24, died in a hospital in St Louis, Missouri, on Thursday morning (local time). She'd been shot in the chest.

Nathanial R Hendren, 29, has been charged with involuntary manslaughter and armed criminal action in relation to her death.

Local police are now investigating claims that the two off-duty officers were playing a Russian Roulette-style game in Hendren's apartment at about 1am. They would allegedly take turns pointing a revolver at each other, which had one round in the chamber, and pulling the trigger.

Hendren's partner, who was also at the apartment, is said to have tried to discourage the other two officers from playing the dangerous game. A police statement says the unnamed officer was leaving the apartment when he heard the shot, and came back into the room to see that Ms Alix had been shot.

Her death was initially being treated as an accident, but unspecified new evidence emerged on Friday (local time) which prompted St Louis circuit attorney Kimberly M Gardner to file charges against Hendren.

"This is a devastating incident for Katlyn Alix's husband, family, parents and for our entire community," Ms Gardner said in a statement.

"I will hold people accountable regardless of their profession, public status or station in life. As much as it saddens my staff and me to file these charges, Katlyn and her family deserve justice."

A friend and colleague of Ms Alix has set up a GoFundMe to raise money to cover the costs of her funeral. So far more than US$7500 (NZ$7878) has been fundraised.

The investigation continues.

Newshub.