A preliminary investigation into the gun violence indicated the shootings "stemmed from a domestic-related dispute," the Muscatine Police Department said in a statement.

The "series of homicides" occurred Monday at two residences and a business in Muscatine, police said.

Muscatine police said the alleged gunman killed six family members, then himself, as part of a domestic dispute.

7 dead, including lone suspect, in series of shootings across Iowa's Muscatine