Nicholas Diemel, 35, according to the authorities, and his 24-year-old brother Justin Diemel were traveling to a Missouri farm to complete a cattle business that has been running for several months, police said.
The brothers enter into a contract with farmers in several states to raise livestock for them, CNN subsidiary KCTV reported. The farm authorities in Braymer, Missouri, are looking for one of several farms they wanted to visit last week.
But on July 22, the rented truck they had used was found abandoned on a commuter property and since then no one has heard of them.
The authorities initially told reporters that they were confident that the brothers would be found. Then, late last week, the case became a death investigation.
"What has changed is … locating the truck and working on various clues with investigators," said Larry Fish, Sheriff of Clinton County, during a Monday news conference.
The authorities arrested Garland Nelson, who admitted to driving the brothers' truck from his farm to the property and leaving it there, Fish said.
So far, Nelson has worked with government agencies, Fish said.
Rain has slowed down the search
Many authorities still do not know it.
Fish said the police searched Nelson's farm and other properties to track down the brothers. But the weather did not make it easy.
"We've had pretty heavy rains in the last few days," he said Monday. "That definitely stopped us."
And the investigators are also pursuing several tips and clues that have invaded, Fish said.
"Hopefully, in the future, we will be able to put all the pieces off the puzzle together," he said.
Nelson has previously committed fraud
"The stuff plays an important role," he said.
Nelson's three-part scheme of fraud involved, according to the law firm, credit fraud, livestock sales and insurance fraud.