A San Pedro man is the third person to be arrested in connection with the fatal shooting of an off-duty Monterey Park police officer in Downey earlier this week.

Gerardo Magallanes, an 18-year-old San Pedro resident, was arrested Thursday and booked for murder, the Downey Police Department confirmed.

He is being held in lieu of $2 million bail.

Carlos Daniel Delcid, 20, and a 17-year-old were arrested earlier this week after Delcid shot Gardiel Solorio, 26, five times during a robbery attempt in the parking lot of an L.A. Fitness in Downey, officials said.

When Solorio was confronted at gunpoint, he put his car into reverse, but Delcid opened fire at close range, according to police.

Solorio died at the scene.

The teenager served as driver of Delcid’s car during the attack, police said.

Officials declined to provide more information about Magallanes or his suspected involvement in the fatal shooting, as they do not want to jeopardize the investigation, according to Lt. Cooper of the DPD.