SANTA BARBARA, Calif. -

Four suspects were arrested on suspicion of firearm and drug related offenses following a routine traffic stop on Monday. One suspect, Ronald Wallas Contreras, is a Santa Barbara area gang member and is on parole for robbery, police say.

Another suspect, Alvaro Pinedo, is on probation for vandalism and stalking, officials say. Pinedo did not acknowledge this fact when initially asked, it became apparent when an officer conducting a pat-down for weapons noticed that Pinedo was wearing a GPS ankle monitor, according to police.

Contreras, 29, was arrested and booked into Santa Barbara County Jail on charges of possession of a loaded firearm, possession of methamphetamine and others. His bail is set at $100,000 with a no-bail parole hold.

Three others, Pinedo, Jamie Gonzalez and Stephanie Herrera were also booked into Santa Barbara County Jail on drug and gun charges.