Updated

A Colorado man has pleaded guilty in connection with the death of his girlfriend's half-sister during an apparent imitation of the "Mortal Kombat" video game.

The Weld County prosecutor's office says 18-year-old Lamar Roberts pleaded guilty Monday to knowingly causing a death through child abuse.

Prosecutors say Roberts and 17-year-old Heather Trujillo were baby-sitting Zoe Garcia a year ago. They say they kicked, hit and slammed the girl to the floor.

Trujillo pleaded guilty in May to negligently causing a death through child abuse. She must complete six years in Colorado's youth offender system.

Sentencing for Roberts is set for January.