Officials say Iowa Division of Narcotics Enforcement agent Daniel Stepleton acted with “reasonable force” when he fired his gun four times, killing Ivan Carl Hardemon and injuring Demarco Dudley during an undercover narcotics operation with another narcotics agent.

Johnson County prosecutor Janet Lyness wrote in a press release that Stepleton’s actions were investigated and reviewed.

According to a press release, Stepleton made arrangements to purchase illegal drugs and arrived at the Breckenridge Trailer Court on Aug. 16.

On Aug. 19, Norman Dudley turned himself in at the Johnson County Jail, joining the other two people of interest in the case, Demarco Dudley and John Mulbah.

Mulbah had been charged on Aug. 13 with a controlled-substance violation after he allegedly sold approximately 10.1 grams of a cocaine base to an undercover narcotics agent.

Steven Briggs, an assistant professor of criminology at the University of Northern Iowa, said use of deadly force is unusual, given the number of arrests police make in a given year.

“The use of deadly force is rare,” he said.

Briggs said there are roughly four instances a year in Iowa in which deadly force is used, while there are at least 115,000 arrests.

On the average, he said, the use of deadly force in Iowa has declined as a result of the 1985 U.S. Supreme Court decision Tennessee v. Garner, which changed the definition on when deadly force could be used from a “fleeing felon” to “threatened life.”

“Police have resisted using deadly force in the last couple of decades, and we have seen a reduction since the Supreme Court decision,” Briggs said.

Stepleton fired his gun after a masked man had felt it during a pat down, and then Hardemon aimed his gun at Stepleton’s head, which included him touching the barrel of his gun to Stepleton’s head and making statements about killing Stepleton and the other officer.

According to online court documents, Demarco’s Dudley’s preliminary hearing is set for 2:30 p.m. today; he will be charged with felony first-degree robbery.

Norman Dudley’s preliminary hearing is scheduled for 2 p.m. Thursay, and his arraignment is scheduled for 2 p.m. Friday.

Mulbah’s preliminary hearing for his controlled-substance charge is also set for 2:30 p.m.today, and he will be arraigned at 2 p.m. Friday.