DESOTO, Texas — Doris Stevens' son, a Navy veteran who traveled the world for work and pleasure, suddenly stopped answering her phone calls in 2016. Stevens said she spent years trying to find out what happened, appealing to authorities to no avail.

Earlier this month, Stevens received a grim answer when maintenance workers found Ronald Wayne White dead on the floor of his apartment in a Dallas suburb. The condition of his body indicated White had been dead for an "extended period," according to the Dallas County Medical Examiner's Office, possibly since around the time his mother last heard from him three years ago.

"A part of me is missing and I'm not going to ever see him again," Stevens told Stars and Stripes last week. "I want answers."

A spokesman said the medical examiner's office could not discuss the condition of White's body or his cause of death until an autopsy has been completed. Police in DeSoto, where White was found, are continuing to investigate but they suspect White's death may be linked to his diabetes and have found no indication of foul play, Detective Pete Schulte said.

White's third floor, corner apartment was locked from the inside and there was no odor in the hallway, Schulte said. White appears to have died soon after moving into the DeSoto Town Center Apartments on a month-to-month lease in November 2016, the detective said.

Stevens said she last spoke with her son that month, soon before he was set to move and turn 51. When months passed and she hadn't heard from him, Stevens said she called police in the Dallas area out of concern but also told them that her son loved to travel and might be on a trip.

A "highly unusual" confluence of circumstances allowed White's death to go undetected for years, said David Margulies, a spokesman for the apartment complex.

White worked as an independent defense contractor and his rent was withdrawn from an account linked to his Navy retirement, Schulte said.

Margulies said White's family didn't know he had moved into the apartment and that no friends or employer asked after him. White was known to travel frequently, and when staff checked on the apartment and got no response they assumed he was out of town, Margulies said.

"His mail didn't pile up. His rent was paid automatically," Margulies said. "All of the things that would have normally triggered a welfare check just didn't take place in this situation."

It wasn't until workers looking into a water issue drilled through the lock on White's door that anyone realized he'd died, Margulies said.

"Now as I look back, all the while I'd been crying about my son in Dallas, my son was dead in that apartment complex and I didn't know," Stevens said.