A bomb squad was called after a small homemade explosive device was brought into an Alameda County courthouse in downtown Oakland on Monday morning, authorities said.
A man carried the device at about 9 a.m. into the Wiley W. Manuel Courthouse on Washington Street, where it was detected at a security checkpoint, sheriff's spokesman Sgt. Ray Kelly said.
The man told authorities that it had been planted on his car by someone.
The device was a "a very crude homemade explosive that was about the size of a golf ball," and was detected at the court's security checkpoint, Kelly said.
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The man is connected to a civil lawsuit at the court, according to the sheriff, but no other details were released.
The sheriff's bomb squad responded and the scene was deemed safe, the sheriff's office said on social media.