Carlos Casillas-Flores, a relative of the accused, was arrested in the Aurora shooting and killing of four people. | Media Pyro

Aurora police say they have arrested a relative of a suspect in the shooting deaths of four people.

Fugitive Joseph Mario Castorena, 21, killed four victims in a domestic violence incident on Oct. 30, police said.

Carlos Casillas-Flores, 22, was arrested Thursday in an investigation of accessory after the fact to first-degree murder, police said.

“Detectives do not have evidence at this time that Carlos was directly involved in the shooting that killed four people, but investigators found that Carlos (Casillas-Flores) helped Joseph (Castorina) avoid fear,” according to a Thursday news release.

Last week, police arrested Castorena’s brother, 18-year-old Juan Angel Castorena, in a related investigation of first-degree murder.

Aurora homicide investigators are continuing to work with local, state and federal law enforcement agencies to arrest Joseph Mario Castorena, according to the news release. Casillas-Flores was arrested in Denver by Aurora police.