vigil was held Sunday night in the hometown of a New Hampshire couple whose bodies were found buried in at a South Texas beach. Authorities say the deaths of 48-year-old James Butler and 46-year-old Michelle Butler are being investigated as homicides.

"At present law enforcement officers are working on the investigation and are working on identification of persons of interest and attempting to find the whereabouts of the victims' truck and RV trailer," the release stated.

A deputy on October 27 located a woman's remains in a shallow grave on Padre Island, near Corpus Christi, the sheriff's office said. Chief Deputy Jaime Garza said a man's body was discovered beneath the first body on Monday.

The sheriff's office had announced last week that the Butlers were reported missing, along with their truck and RV. Relatives said the pair had been traveling the country in a recreational vehicle since June of 2018 and was last heard from on October 16. They said they believed the Butlers visited Padre Island.

Investigators said both vehicles were last seen on surveillance video between October 20 and 21 crossing the U.S.-Mexico border. The driver was not James or Michelle, reports CBS News' Meg Oliver.

"It's not very often we have a mobile crime scene if the crime was committed say in the trailer," said John Matthews of Community Safety Initiative.

They most recently had worked as gate guards for oil rigs in Texas, checking vehicles in and out, said Butler's sister, Deborah van Loon, of Rumney, New Hampshire on Saturday.

They were in frequent contact with family and shared photographs of their trip on Facebook, she said.

"We all loved what they were doing and they loved sharing it with us," said van Loon who described her brother as "an all-around really wonderful man."

He had retired from the Navy in 2010 and "loved to joke around about everything," she said. He came back to Rumney, New Hampshire, after he retired when his mother was dying of cancer, van Loon said. He met Michelle then and they married in 2015, she said.

The couple was likely headed to a part-time job in Fort Lauderdale, Florida, and due to arrive there in November to sell Christmas trees, van Loon said.

The Butlers had set up their truck and RV near Beach Market 263 on Padre Island on Oct. 15, the sheriff's office said.