A suspected bomb likely was some type of homemade firework, but Tracy police called in a San Joaquin County Sheriff’s Department bomb squad anyway to take the device from a car that was stopped near Tracy High School.

Lt. Greg Farmanian of the Tracy Police Department said it was unclear if the device even had active explosives, a fuse or a detonator, but it looked enough like an explosive — somewhat like an M-80 firecracker — that police handled it carefully.

Police found the device Friday afternoon after an officer stopped a white Honda Accord believed to be connected to a strong-arm robbery at the Sonic Drive-In at West Valley Mall three weeks ago.

Farmanian said officer Steven Clayton recognized the driver as a man who reportedly pushed a restaurant carhop to the ground and stole $100. The car in that case was described as a white four-door Honda, similar to the car police stopped Friday.

Clayton pulled the car over on 12th and East streets next to Tracy High, chased the 19-year-old man for a couple of blocks and took him into custody.

Farmanian said the man, identified as Christopher Mahoney, 19, was arrested on suspicion of robbery. Police found the suspected explosive in the trunk when they searched the car.