Suspect in security guard’s shooting death in Pacific Beach pleads not guilty to murder

A 49-year-old man pleaded not guilty on Friday to the murder of a security guard near Crystal Pier in Pacific Beach last month.

At an arraignment in the downtown courthouse on Friday, San Diego County Deputy District Attorney Jessica Coto said the defendant, Brian Mathew McColley, faces multiple counts in the shooting of Luis Alberto Quiroz-Arreola, 31, as well as “numerous other charges.” They include felony possession of drugs and weapons. 

McColley was arrested Tuesday around 4 p.m., almost a month after Quiroz-Arreola’s death. The San Diego Police Department’s Special Investigations Unit found him in the 300 block of Cedar Street in El Cajon, officials said. 

McColley already had an outstanding warrant for his arrest for an unrelated offense, police said. He was taken to San Diego Central Jail on that warrant as well as the first-degree murder charge. 

McColley, Coto said, presents a “grave danger to the community, as he has shown a violent pattern of conduct, not only in the cases that are currently charged, but also in his prior criminal history.” 

Coto said McColley’s criminal record includes felonies at the both state and federal levels, including multiple armed bank robberies. She also said that she anticipates that he will be charged with additional counts.

McColley could face life in prison. His preliminary hearing is set for April 7, when a “significant portion of the evidence” will be presented, according to Coto. 

Quiroz-Arreola was shot shortly after 2 a.m. on Oct. 5 while working at Crystal Pier. Employees of a nearby bar started CPR at the scene and medics continued first aid, but the victim died at the hospital.

Pacific Beach Town Council president Charlie Nieto said in an email that this year had been “truly heartbreaking” for the Pacific Beach community. 

“We have witnessed numerous tragic fatalities and injuries throughout 2026, and just within the last month our community was horrified by the senseless loss of life on our boardwalk at the Crystal Pier,” Nieto said. “With the arrest of the suspect from this crime, we are one step closer to justice for the victim’s family.”

Police said the motive for the shooting remains unknown and that the investigation is ongoing. 

SDPD asked that anyone with information regarding this case call the Homicide Unit at (619) 531-2293 or the Crime Stoppers at (888) 580-8477.