DENVER — Sources have confirmed to FOX31 that the 21-year-old suspect arrested for first-degree murder in the shooting death of a Denver Police officer admits he is in a gang, and claims a specific Denver gang affiliation.

Rollin Oliver was arrested Sunday night, accused of shooting 32-year-old officer Celena Hollis in the head. Sources said a fight broke out between rival gangs at the City Park Jazz Concert. The altercation took place at approximately 8 p.m. Sunday and Hollis was one of several officers working off-duty at the event.

As she and others responded to the fight, Hollis was shot in the head and paramedics were unable to save her life.

Police said a witness gave them a description of Oliver, and he was quickly apprehended and arrested with a gun in his possession.

Oliver’s aunt Roxanne Shaw said she never saw him with a gun and did not know he was in a gang. But she said he used to deal marijuana. Oliver’s Facebook page describes him as being in “Park Hill pharmaceuticals”.