Northeast Man to Use Insanity Defense for Attempted Murders of Peace Officers

A northeast Iowa man plans to use an insanity defense in two cases against him, including his alleged attempted murder of peace officers. 

The Iowa Department of Public Safety (DPS) said the Howard County Sheriff’s Office (HCSO) received a 911 call from 45-year-old Mark Zweibohmer to conduct a welfare check at his residence near Elma on May 28th. When officers arrived, Zweibohmer allegedly began shooting at responding officers, who returned fire.

The incident also involved Cresco Police, the Winneshiek County Sheriff’s Office and the Iowa State Patrol. There were no injuries reported. 

Zweibohmer is charged with four counts of attempted murder of a peace officer, including Howard County Sheriff Rick Busch and deputies Ben Hillyer, Jake Hofstra, and Wyatt Ronnebaum. Zweibohmer has entered a not guilty plea to the Class B felonies and his trial date was recently continued to February 4, 2026, in Howard County District Court.

On Monday (07.28), his attorney, Judith O’Donohoe of Charles City, filed notice that Zweibohmer intends to rely on a defense of insanity and/or diminished responsibility. The defense says they’re awaiting results from their own evaluation of Zweibohmer, with those findings to be provided to the prosecution to allow them to pursue their own evaluation of  Zweibohmer’s mental state.

Zweibohmer is held in the Winneshiek County Jail on $200,000 cash bond.

Zweibohmer is also slated for trial on February 4, 2026, for his arrest last September on charges that include third degree burglary, interference with official acts causing bodily injury, eluding, OWI, operating a vehicle without owner’s consent, and five counts of first-degree harassment. 

He is also pursuing an insanity defense in that trial.