The skeletal remains found inside a truck recovered from a North Texas lake belongs to Helen Holladay, a woman who disappeared 35 years ago after an argument with her husband, authorities told

The Hood County Sheriff's office said Thursday that investigators were able to confirm the discovery by dental records.

A passer-by discovered the partially exposed 1970s-model Chevy truck last week in Lake Granbury after the lake's water level dropped, thanks to the state's ongoing drought, and revealed a portion of the vehicle. The truck was found far away from any road or parking lot near the lake, and investigators "don't believe it was an accident," Hood County Sheriff Roger Deeds said.

While inspecting the truck's cab, investigators found human skeletal remains, pieces of clothing and a purse containing objects with Helen Holladay's name on them. Holladay was 45 years old when she disappeared in September 1979. Her husband, Herman, was a suspect in her disappearance but was never charged. He has since died.

Deputies had responded to a call about a domestic disturbance at the Holladays' house the night she went missing in September 1979. Witnesses reported seeing Helen Holladay leaving the house, though there was not enough evidence to charge her husband, Deeds said.

The truck was discovered Thursday by a Granbury city worker.

Deeds noted that investigators searched the lake numerous times following Holladay's disappearance, but the murky waters and the fact that the truck was covered in silt made it nearly impossible for divers to see. But Texas' record-breaking drought has brought the lake to its lowest levels in years.

Initial inspection of the skeletal remains revealed no signs of trauma, but detectives can't yet say whether foul play was involved in her death, Deeds said.

"It's still too early in the investigation to rule in one direction or the other," he said, adding that a forensic investigator with the University of North Texas at Denton is expected to inspect the remains.

Fox News' Edmund DeMarche and The Associated Press contributed to this report