Prosecutors say 23-year-old Sir Mario Owens, the accused triggerman in a double slaying, lived by the motto "You snitch, you die."

During opening statements in Owen's first-degree murder trial Tuesday, prosecutors say Javad Marshall-Fields told friends less than 24 hours before his death that he feared for his life.

Owens is facing the death penalty in the deaths of Vivian Wolfe and fiance Marshall-Fields, who was scheduled to testify against Owens and another man in a separate case. Wolfe and Marshall-Fields were shot to death in a vehicle at an Aurora intersection in June 2005.

Owens was later convicted of killing Gregory Vann, a friend of Marshall-Fields.

Marshall-Fields was to have testified at Owens' trial.