A Santa Maria couple is behind bars this morning. Michael Cantero and Christina Pichardo are suspected of robbing a U.S. mail carrier at knifepoint last week. They got away with the postal carrier’s mail keys. After the robbery, police received several reports of stolen property from secured mailboxes. The couple was taken into custody early yesterday morning at Motel 6 on North Preisker. Both are facing numerous felony charges.