GREELEY, Colo. -- The teenaged girl accused of killing her 7-year-old step-sister appeared in court in Weld County Wednesday.

Heather Maria Trujillo, 16, and her boyfriend, Lamar Roberts, 17, have been charged as adults with felony child abuse resulting in death in connection with the Dec. 6 death of Zoe Garcia.

Trujillo and Roberts were baby-sitting Garcia at the time, according to police.

Trujillo told Johnstown Police that she and Roberts were imitating the Mortal Kombat video game when they began attacking Garcia. An arrest affidavit said the two kicked, karate-chopped and body-slammed slammed Zoe while imitating the video game.

When Garcia lost consciousness, Roberts and Trujillo tried to wake her up by placing her in a bathtub, the affidavit said. They also cracked open an egg and put it in her mouth to make sure Garcia was not "messing with them."

The teens waited for 15 minutes before contacting police because they were afraid "the cops were going to get mad" because teens were watching a child, the affidavit said.

Autopsy records showed Garcia suffered a broken wrist, more than 20 bruises and injuries to her neck and spine. The Weld County Coroner’s Office said she died from blunt-force trauma.

Trujillo is due back in court on Jan. 30. In the meantime, her lawyers are in negotiations with the district attorney's office. Both Trujillo and Roberts are being held under $100,000 bonds.

They could each face 16 to 48 years in prison if convicted.