U.S. Navy veteran James Butler, 48, and wife Michelle, 46, were found buried in a shallow grave in Padre Island, Texas

By Steve Helling
November 04, 2019 02:32 PM

Police are hoping that newly discovered surveillance video will be the key to solving the mysterious case of the New Hampshire husband and wife who were found buried on a Texas beach.

U.S. Navy veteran James Butler, 48, and his wife Michelle, 46, were found buried in a shallow grave on a remote part of Padre Island. Their bodies were found on Oct. 27 and 28, weeks after they disappeared.

Authorities have ruled the case a homicide.

The couple had gone camping with their truck and RV trailer on Oct. 15, and relatives reported them missing a week later on Oct. 22 when they hadn’t heard from them since Oct. 16. Family members say the the Butlers were avid travelers who were criss-crossing the country on a trip to Florida, where they planned to sell Christmas trees.

RELATED: Bodies of Missing N.H. Couple Found Buried on Texas Beach

Their bodies were discovered after their cell phones pinged in the area, reports ABC News. The remains took several days to identify because they were badly decomposed and had no identification.

Authorities now say that surveillance video may give a clue to the person or persons responsible for their death. The couple’s vehicles were last seen on surveillance video between October 20 and 21 crossing the U.S.-Mexico border. The driver was neither James nor Michelle, according to CBS News.

The unnamed driver is now a person of interest in the unsolved killings, says the Kleberg County Sheriff’s Office

“Our heartfelt condolences go out to the family and friends of the Butlers on the tragic loss of their loved ones,” the sheriff’s office said in a news release.

Want to keep up with the latest crime coverage? Sign up for PEOPLE’s free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases.

While authorities have ruled the case a homicide, they have yet to release any information on the cause of death.

Investigators, who are currently working to identify any suspects, told CNN they will release more information about the case on Monday at a news conference.