IOWA (AP)— Three family members were shot to death while camping in a state park in eastern Iowa Friday, and the suspected gunman died of a self-inflicted gunshot wound, police said.

Officers responded to reports of the shooting at the Maquoketa Caves State Park Campground before 6:30 a.m. Friday, the Iowa Division of Criminal Investigation said in a statement. Officers found three people fatally shot in a tent on the campground, division assistant director Mitch Mortvedt said.

The three victims were related, Mortvedt said. He did not provide their names or ages, or explain how they were related.

Officials immediately evacuated everyone from the park, a children’s summer camp on the grounds and the campground. Once the evacuation was complete, the only registered camper not accounted for was 23-year-old Anthony Sherwin, Mortvedt said.

“He was known to be armed. That of course heightened our awareness as well,” Mortvedt said. Iowa allows people with permits to carry firearms virtually anywhere in the state. Officials did not say if Sherwin had a permit.

Using a plane to help search the area, law enforcement later found Sherwin dead from a self-inflicted gunshot wound in a wooded area of the park. Sherwin came from Nebraska, and investigators don’t believe he had any prior relationship with the victims, Mortvedt said.

Mortvedt said he could not say whether Sherwin had a criminal record. A search of online court records in Nebraska and Iowa did not produce any record of prior criminal behavior.

Autopsies on Sherwin and the victims were scheduled to be performed over the weekend, Mortvedt said, and more information would likely be released based on those findings.

The park remained closed Friday.