Two brothers from Wisconsin vanished on a business trip to Missouri — and human remains have been discovered in the search for the pair, authorities said.

Nick Diemel, 35, and his brother Justin, 24, never boarded their flight home on July 21 after traveling on business to a farm in Braymar, Missouri, where remains were later found, news station KMBC reported.

“The cause of death has not been determined,” Clinton County Sheriff Larry Fish said Wednesday. “This is still an active investigation and the human remains have not been identified at this time. Investigators are still working with Frontier forensic doctors to figure out what took place.”

Officials said the farm is run by 25-year-old Garland “Joey” Nelson, who was arrested last week in the case.

Nelson is accused of tampering with the vehicle rented by the brothers. The truck was recovered in a parking lot near Holt with the keys still in the ignition, engine running and lights on, authorities said.

Nelson was ordered Monday held without bond at the Caldwell County Detention Center, according to court records.