MELBOURNE BEACH, Fla. (WFLA) — Family members of a missing Florida man whose boat washed ashore with the motor running said they still question some things about his disappearance.

According to a WPBF report, Dale Hossfield, 68, left the Fort Pierce Inlet around 2 p.m. on May 18 on his 29-foot ProLine fishing boat. The boat was found four days later, washed up about 50 miles north in Melbourne Beach with the motor still running, but Dale was nowhere to be found.

In their first public statement since the disappearance, Dale’s children said his disappearance seems highly suspicious.

“I think there’s a lot of things that just don’t add up. I think there’s some questions that remain around his disappearance and death,” said son Gabriel Whalen, a former U.S. Army investigator.

The GPS on Dale’s boat showed it traveled 40 miles out to sea before turning around and coming back. It then showed the boat taking a hard turn north toward Melbourne.

“It went out, which was not his normal routine; he was a creature of habit and then it suddenly does some turns and goes all the way up to shore in Melbourne which he never went to,” Gabriel said.

“The fact that he was out alone for that length of time and that far from shore doesn’t seem to make sense. He doesn’t seem to be fishing — there was no bait or anything like that on the boat,” Dale’s daughter, Melinda, said.

Brevard County Sheriff’s Office deputies found Dale’s wallet, keys, cell phone and shorts on the boat. Despite the Coast Guard searching over 3,200 square miles in clear conditions, Dale was never found.

“My thought is he got wrapped up in something, and I think, I think somebody was out on the water with him that day, and I think they disposed of him,” Gabriel said.

The Florida Fish and Wildlife Commission is expected to release its final report on the investigation into Dale’s disappearance soon.