CORPUS CHRISTI, Texas — Authorities say police have arrested a man in Mexico who’s suspected of stealing a car that belonged to a New Hampshire couple found buried at a South Texas beach.

Kleberg County Sheriff Richard Kirkpatrick told KIII-TV in Corpus Christi, Texas, on Wednesday that Adam Curtis Williams was arrested by authorities in the Mexican state of Jalisco (hah-LEES’-koh) on felony theft charges.

Authorities believe the 33-year-old Logan, Utah, man and Amanda Noverr might have had contact with 48-year-old James Butler and 46-year-old Michelle Butler. They released a surveillance photo of Williams and Noverr crossing the border into Mexico in a car belonging to the Butlers.

James Butler’s sister Debbie Van Loon told WMUR-TV in Manchester, New Hampshire: “We’re glad to hear the arrest has been made and await what’s next.”

Officials say the Butlers’ deaths are being investigated as homicides. Their bodies were found last week in a shallow grave on Padre Island, near Corpus Christi.