POTOSI, Wis. -

An Iowa man camping on the Wisconsin side of the Mississippi River drowned Friday afternoon, officials said.

The Grant County Sheriff's Department said it responded to a report of a possible drowning in the Mississippi River at 4:38 p.m. north of Potosi, Wisconsin.

Jerry S. Thill, 53, of Dubuque, Iowa, had been camping with four other Dubuque men  on an island on the Wisconsin side of the river across from Finley's Landing Park, which is on the Iowa side of the river.

In a news release, the sheriff's office said Thill had gone into the river "to check why the fishing was so bad." The other four men -- 27-year-old George Jackson, 25-year-old Devin Cullen, 50-year-old Steven A. Kruckenberg and 23-year-old Steven C. Kruckenberg -- told authorities Thill was in the water up to his chest and initially appeared to be fine.

Thill suddenly appeared distressed and tried to swim, according to the report.

The younger Kruckenberg swam to Thill but was not able to keep a strong hold on him. Thill went under water and did not resurface, authorities said. The men got out of the water and called 911.

An Iowa Department of Natural Resources boat and several area fire departments responded to the area. The boat used sonar to locate the body and about an hour later, Thill was pulled from the river. The Grant County coroner pronounced Thill dead on the shore in Potosi.