A 23-year-old inmate at San Quentin State Prison was arrested Friday for allegedly killing his girlfriend in Half Moon Bay last year, authorities said.

San Mateo County investigators identified Tristan Cecil, who had been serving a three-year sentence for drug sales, as the suspect in the slaying of 18-year-old Kimberly Quiroz after a 15-month investigation.

On Feb. 22, 2018, deputies responded to reports of a shooting at a home on the 200 block of Poplar Street in Half Moon Bay. They found Quiroz suffering from a gunshot wound and she was taken to a hospital by helicopter, officials said. She died from her injuries on March 3, 2018.

On Friday, Cecil was transported from San Quentin State Prison to the San Mateo County Jail, where was booked on suspicion of murder. He is being held on $11 million bail, according to jail records.

Cecil’s next court date is Tuesday.

Anyone with information about the investigation is asked to call detective Nick Boragno at 650-363-4064.

Ashley McBride is a San Francisco Chronicle staff writer. Email: ashley.mcbride@sfchronicle.com Twitter: @Ashleynmcb