Adaisha Miller was celebrating what would have been her 25th birthday Monday. Chief Ralph Godbee called her death a tragic, “unfathomable” accident.

“We are profoundly sad at their loss,” he said, referring to Miller’s family.

Godbee said the gun was in a waist holster made of soft material, which would have allowed the trigger to be activated. He said there’s no evidence the officer fired the gun, and he believes the gun discharged after Miller hugged the officer from behind early Sunday during a party at the officer’s home.

“There was some manipulation along the officer’s waistline (that) he did not control,” Godbee told reporters.

The officer, whose name was not released, is on desk duty while the case is fully investigated. Police union lawyer John Goldpaugh said the officer didn’t know Miller.

“This was just a freak accident,” Goldpaugh told the Detroit Free Press. “They were having a party and the next thing, a woman is dead. He’s devastated by what happened.”

Police said previously that the bullet punctured Miller’s lung and hit her heart, and she died at a hospital.

Her mother, Yolanda McNair, said the shooting never should have happened.

“All she wanted to do was enjoy the weekend for her birthday,” McNair told WDIV-TV. “She had every right to enjoy turning 25 and look beyond that.”