Charging documents show a man accused of killing a teenage brother and sister in Utah shot them multiple times during a group fight and warned others as he drove away that "they would be next" if they said anything.

Prosecutors have charged the 28-year-old Mario Cervantez-Angel with two counts of aggravated murder, which carries the possibility of the death penalty.

Witnesses says a fight broke out on July 6 in a Salt Lake City suburban apartment complex when Cervantez-Angel and three others showed up to confront Jose Izazaga and Abril Izazaga. Authorities said previously the fight started over a T-shirt.

They were shot when Jose Izazaga pulled out a knife to defend his sister after authorities say Cervantez-Angel slammed her against a brick wall.

Cervantez-Angel is being held in jail on $2 million bail. He doesn't have an attorney yet.