Updated

A man who admits killing a woman after a Halloween party and stashing her body in the woods was convicted of first-degree murder Tuesday in Michigan as jurors rejected his claim that the death was an accident.

Chelsea Bruck, 22, disappeared after attending a party with hundreds of people in Monroe County's Frenchtown Township in 2014. Her body was found six months later.

There was no dispute that Daniel Clay killed Bruck. But jurors had to decide whether it was intentional as prosecutors alleged or an accident during aggressive sex in Clay's car as he claimed.

Clay now faces a mandatory sentence of life in prison without a chance for parole. DNA on Bruck's Poison Ivy costume led investigators to Clay in 2016.

The verdict means Bruck's family is "nearing the end of a 31-month ordeal," prosecutor Michael Roehrig told reporters, noting the date of her disappearance. "It's a huge emotional relief for everyone involved."

Roehrig told jurors that Bruck's facial injuries showed Clay beat her.

"The defendant murdered Chelsea Bruck, then discarded her lifeless, naked body," Roehrig said. "Clearly he never wanted to be caught."

Clay denied striking Bruck during his testimony Monday. He said he consumed drugs and alcohol at the Halloween party and offered Bruck a ride when he saw her on the road.

"I didn't mean for this to end like this," Clay said.