Investigators allege that three people used homemade devices to block security systems in some mailboxes at the Camarillo Post Office and to steal mail.
The devices kept mail in part of the mailboxes. The mail thieves later returned to use a second device to fish out the mail.
Last month, postal workers noticed one of the homemade devices. A surveillance camera gave investigators a suspect and vehicle description.
This week, an automated license plate reader system notified sheriff’s deputies the vehicle was in the area.
Deputies stopped the vehicle and arrested two men and a woman from Los Angeles. Deputies say a search turned up some homemade mail-theft devices, stolen mail, stolen checks, and burglary tools.