Search dogs on Sunday found decomposed remains that authorities believe are those of Fred Byrne, 49, of Big Rapids.
Carter County (Mo.) Sheriff Richard Stephens said the remains were badly decomposed and it wasn't clear how long identification would take.
The autopsy was initially planned for Monday, but authorities said it would be performed Tuesday in the southeast Missouri town of Farmington.
Byrne dropped off his son at Hope College in Holland on Feb. 12, then visited his mother in Holland. He had not been seen since.
His Chevrolet Malibu was found two days later 560 miles away, along a service road in the south-central Missouri forest, near the town of Van Buren. Stephens said the remains were discovered by search dogs about a quarter-mile from the car.
Stephens had asked a canine rescue team to visit the area where the car was found. He said the dogs were on-site for about three hours when the remains were found shortly after noon Sunday.
"We hadn't given up on that case," Stephens said.
Earlier searches, including an aerial search of the forest, found nothing.
Byrne is an attorney and a prominent member of the Big Rapids community, serving on the city's parks board. His wife, Diana, is president of the Big Rapids school board.
In a posting Monday on the Facebook page dedicated to finding Byrne, Diana Byrne thanked police "and all other agencies, searchers, family, friends and many others who have reached out in support." The posting said funeral arrangements were pending.