July 9, 2012 -- A friendly hug at a Detroit house party proved fatal for a woman after she accidentally discharged an off-duty cop's handgun.

Adaisha Miller, 24, attended a fish fry at the home of an off-duty Detroit police officer on Saturday and, at around midnight, began to hug or dance with the officer from behind and accidentally set off his gun, according to Detroit police chief Ralph Godbee, Jr.

The police department didn't release the name of the officer but said that he has been cooperative with an internal investigation launched in the wake of the shooting and is shocked at what happened.

Godbee said that the officer had been concealing his department-issued .40 caliber Smith and Wesson semiautomatic hand gun in a holster in his waistband when Miller placed her hands on his waist. Godbee indicated that Miller had seemingly touched the gun in some way, causing it to fire. There is no safety switch on the weapon, he said.

"I don't think I'm giving anything away by saying this but for the sake of transparency, it is possible for the trigger to be manipulated with that type of holster," Godbee said. "Typically the barrel is facing down, but the preliminary investigation indicates that there was some manipulation along the officer's waistline that he did not control and subsequently the weapon discharged."

Godbee said that there was no indication from evidence or witnesses that the officer had placed his hand on the weapon. The investigation will include forensic analysis by the Michigan State Police and a medical examiner's report.

"He is very remorseful of the incident and the tragic nature of this young lady losing her life in the manner she did," Godbee said.

Miller's mother, Yolanda McNair, told the Detroit Free Press that she has been told different versions of the events leading up to her daughter's death and can't understand why the officer was armed at his own party.

"The story keeps changing. There's no logical reason," she said. "Why do you need a weapon with a round in the chamber?"

Police department spokeswoman Cassandra Lewis said that the prosecutor's office would decide whether any charges would be pressed in the case. The officer has been placed on adminstrative duty during the investigation, Godbee said.

Amy Driver, a gun safety expert, said that it was "entirely possible" that if someone was placing their hands on the officer's waistband that the weapon could become loose from the holster and then discharge if it were pressed back down toward the holster.

"It sounds like she pulled on his waistband, and if that shifted his waistband, the gun could have come up out of the holster a little bit, and his instinct could be to push the gun back in holster. If something got caught on trigger, it could have fired," she said.

Driver said that investigators would likely find a hole in the side of the officer's pants, where the bullet left the gun and traveled to Miller.