(CNN) Missouri authorities have been combing through a 74-acre farm in hopes of finding out what happened to two Wisconsin brothers who have been missing since last week.

Nicholas Diemel, whom authorities said is 35, and his 24-year-old brother, Justin Diemel, traveled to a Missouri farm for a cattle business deal that had been going on for a few months, police said.

The brothers contract with farmers in multiple states to raise cattle for them, CNN affiliate KCTV reported. The Braymer, Missouri, farm authorities are searching, was one of several farms they were going to visit last week, the affiliate said.

But on July 22, the rented truck they'd been using was found abandoned in a commuter lot and no one's heard from them since.

Authorities initially told reporters they were hopeful the brothers would be found. Then, late last week, the case turned into a death investigation.

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