The authorities in Muscatine, Iowa, said on Monday that they believed a 52-year-old man fatally shot six members of his family in a domestic dispute before killing himself when he was confronted by the police.

The Muscatine Police Department said in a statement that officers were dispatched to a residence at about noon on Monday and found four people dead with gunshot wounds. It said a man, Ryan Willis McFarland, who had left the residence before the police arrived, was “quickly identified” as a suspect.

The police tracked him down on the Riverfront Trail, a public pathway in Muscatine, a city of about 24,000 people along the Mississippi River in eastern Iowa. While officers were talking to Mr. McFarland, “he took his own life,” the police chief, Anthony R. Kies, said at a news conference.

Another man was found with fatal gunshot wounds in a separate residence, and a sixth victim, a man, was found dead at a business venue, he said.

The police believe the shootings “stemmed from a domestic dispute,” Chief Kies said. “At this time, all victims are believed to be family members.”

He said Mr. McFarland had a criminal record but gave no further details about what led to the dispute, the ages of the victims, or how they were related to the suspect or one another.

Two of the victims were students and two others were employees of the Muscatine Community School District, the superintendent, Clint Christopher, said in a statement.