Where was Mark Riesberg found? Investigation underway as missing Calhoun County man found dead

Mark Riesberg, a 54-year-old Calhoun County man, was found dead on Dec. 1, inside a vehicle in Jolley, Iowa, a month after he was reported missing. Riesiberg, who was reported missing by his employer on Nov. 1, was reportedly found dead with an apparent gunshot wound.

Per multiple reports, Mark Riesberg was reported missing by his employer, Essentia Protein Solutions, in Lytton. The 54-year-old's last known contact with people was on Oct. 28.

When investigators who found the missing man’s phone and wallet at his house did not deem the disappearance as suspicious. His car, a tan Chrysler PT Cruiser, was also missing from his home. It's unclear if Riesberg was found inside his missing vehicle.

In the wake of the discovery, police are investigating the case as a homicide. Meanwhile, the circumstances surrounding the disappearance and subsequent death remain unknown.

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Mark Riesberg's sister expressed concerns about her brother's disappearance

According to a release from the Calhoun County Sheriff's Office, a month after Riesberg was reported missing, he was found dead inside a vehicle in Jolley, Iowa, with an apparent gunshot wound.

Authorities added that foul play is suspected but declined to release further information, citing an active investigation.

Earlier this week, shortly before Mark Riesberg was found dead, his sister Mary Brown spoke to KCCI, expressing her concerns for her brother’s well-being.

In the interview, Brown said that it was unlike her brother to take off from his home, where his wallet and phone were found after his disappearance.

"This is not like him. He would never ever go missing. He would never miss work. Something is wrong. We need to do something.” Brown added,

“I don't know if someone came to the door in the middle of the night and needed help, of course, Mark is going to help anybody. I don't know if he went out to help somebody. I just don't know why we can't find him or his car.”

Brown also expressed her frustration with the Calhoun County Sheriff's Office, who repeatedly insisted that her brother left voluntarily, as there was no evidence to indicate any criminal activity:

"I said no, you can't be serious. And they said to tell you the truth, we'll probably find him at the bottom of a pond in a few years. Like just no compassion, are you kidding me?"

At the time, the Calhoun County Sheriff's Office did not address Brown's concerns. As authorities continue investigating, they are yet to disclose additional information in the case. Anyone with information about the incident is urged to contact the Calhoun County Sheriff’s Department.

Meanwhile, the search continues for 53-year-old David Schultz, a truck driver who disappeared in the same area as Mark Riesberg on Nov. 21. However, Calhoun County Sheriff Riley said that he doesn't believe the two missing person's cases are related.