Two brown briefcases left near the Livermore Post Office late Monday afternoon prompted police to evacuate the building and neighboring businesses while investigating the suspicious satchels.
A postal employee notified police at about 4:20 p.m. of the briefcases left at the northwest corner of the building at 220 S. Livermore Ave.
Officers evacuated the post office during the investigation and detonated the brief cases at 7:40 p.m., police said. They were both found to be empty, according to police.
A witness told officers that he saw a light-skinned Hispanic male, who is about 25 years old and was wearing a black baseball cap, drop the briefcases off and then enter a white Saturn Vue, driven by a white woman who is about 40 years old and has red hair.
Livermore police are continuing to investigate the incident with assistance from the U.S. Postal Service and the Alameda County sheriff's bomb squad.