(CNN) -- The man Texas police were searching for in connection with the killings of a New Hampshire man and woman has been arrested, police say.
The Kleberg County Sheriff's Department had issued an arrest warrant on a felony theft charge for Adam Curtis Williams, who was seen in the couple's pickup as he allegedly drove it into Mexico. He was arrested in Mexico and was in the Kleberg County jail as of 11 p.m. ET Wednesday, chief deputy Jaime Garza told CNN.
Kleberg County Sheriff Richard Kirkpatrick told reporters Tuesday that investigators would like to talk to a woman who was seen in surveillance video in the passenger's seat of the truck.
That woman remains in Mexico, but could be extradited to the US, Garza said.
People matching their description were seen crossing the border at Eagle Pass, Texas, District Attorney John Hubert said.
On Monday, authorities released a still from a surveillance camera video that purportedly shows Williams and the woman in the couple's truck several days after the New Hampshire couple last made contact with family and friends.
The remains of James Lawrence Butler III and Michelle Elaine Butler, of Rumney, New Hampshire, were found buried in the sand of a Padre Island beach in late October. They had been missing for about 10 days.
Their deaths were ruled homicides by the Nueces County medical examiner's office. It didn't release information about the cause of death.
The couple on October 15 set up their camping trailer near the spot on the beach where they were found. Someone communicated with them the next day, the release said.
The couple had been traveling around the country since June 2018, taking part time jobs, officials said.
Kirkpatrick said Williams and the woman are from Utah and they have not discovered why they were in Texas.
CNN's Madeline Holcombe, Giovanna Van Leeuwen and Sheena Jones contributed to this report.