(KRON) -- A man who had been arrested in Hercules after allegedly violating his probation by possessing a firearm was transported to the police station, where he picked the lock to his handcuffs with a safety pin, according to police. Hercules Police Department officers pulled over a Pittsburg woma n driving a 2003 Honda Accord coupe around 11:30 p.m. on Friday. Her passenger, a 47-year-old Pittsburg man, was found to be on probation for firearm charges and authorities searched the vehicle. During the search, officers uncovered an unregistered firearm inside a bag that also contained items belonging to the man, police said. The woman told officers that the bag belonged to the man, and he was placed under arrest. The woman was released at the scene. The man was brought to the police station, where he was handcuffed to a bench inside a secured interview room. While officers stepped out of the room, the man “acquired a safety pin from an unknown source,” police said, and “picked the handcuff lock open.” An officer contacted the man through the door of the interview room, and the man “threatened harm and violence against the officer,” according to authorities. The man was eventually convinced to lie flat on the ground, police said, before officers moved in and detained him in handcuffs again. After a thorough search, he was transported to the Martinez Detention Facility for violation of probation, felon in possession of a firearm, resisting a peace officer and threats of violence against a peace officer. ...read more read less