Authorities in Texas said Wednesday that a 33-year-old Utah man was arrested in Mexico on a charge that he stole the truck and RV belonging to a couple whose bodies were found last month on a Texas beach.

The man, Adam Curtis Williams, faces a charge of felony theft, according to the Kleberg County Sheriff’s Office. He was transported to the United States and, as of Wednesday evening, was being brought from Houston to Kleberg County, said Chief Deputy Jaime Garza.

The killings of the couple — James Butler, 48, and Michelle Butler, 45, of New Hampshire — remain under investigation. They had been traveling the country in their RV and were staying at a South Texas beach when they disappeared last month. Their bodies were found buried in a shallow grave on the beach southeast of Corpus Christi, and their truck and RV were missing.

Authorities said at a news conference Tuesday that they believed Williams had absconded to Mexico after stealing the truck and the RV. They said he was seen in a surveillance photograph crossing the border into Mexico with a woman, Amanda Noverr, who remains a person of interest in the case.

Garza declined Wednesday evening to provide more information about how Williams could have been connected to the Butlers or the circumstances of his arrest in Mexico. Garza said that the truck and the RV, which were with Williams when he was arrested, remained in Mexico.

At the news conference Tuesday, authorities said that other people could be involved in the Butlers’ killings.

They have not released details on how the couple were killed.

The Butlers disappeared Oct. 15. More than a week later, a relative filed a missing persons report. Their bodies were found later that month, and Nov. 1, their deaths were ruled homicides.

Investigators used cellphone towers to approximate the Butlers’ last known location, leading them to an area of the beach on Padre Island known as “the bowl” for the way the sand dunes form a depression.