An Iowa man is suspected of fatally shooting six relatives before taking his own life on Monday, authorities said.Muscatine Police Chief Anthony Kies said officers responded to a report of a shooting at about 12:12 p.m. Monday at a home on Park Avenue in Muscatine, a city roughly 50 miles southeast of Cedar Rapids.When officers arrived, they discovered four victims inside the residence suffering from gunshot wounds. All four were pronounced dead at the scene, Kies said during a news conference.Investigators quickly identified the suspected gunman as Ryan Willis McFarland, 52, of Muscatine. Police said McFarland had left the residence before officers arrived.5 FOUND DEAD IN MINNESOTA APPARENT MURDER-SUICIDE: POLICEAuthorities later located McFarland on the city's riverfront trail near a pedestrian bridge."While talking to Ryan Willis McFarland, he took his own life," Kies said.NYC SHOOTING: WHAT TO KNOW ABOUT SHANE TAMURA, GUNMAN WHO KILLED 4 INCLUDING NYPD COP IN MIDTOWN MANHATTANOfficers and emergency medical personnel attempted to render aid, but McFarland was pronounced dead at the scene.As investigators continued examining the case, police developed information suggesting there could be additional victims elsewhere in the city.Officers subsequently discovered an adult male dead from an apparent gunshot wound inside a residence on Mill Street. Investigators later found another adult male dead from an apparent gunshot wound inside a business on Grandview Avenue.FLORIDA MAN SUSPECTED OF KILLING 6 IN SHOOTING SPREE AT 2 RESIDENCES IDENTIFIEDPolice believe all six victims were family members of McFarland."The preliminary investigation indicates the shooting stemmed from a domestic dispute," Kies said.Authorities have not yet publicly identified the victims or released details about their ages and specific relationships to McFarland.A TIMELINE OF THE MANHUNT FOR RURAL MONTANA BAR MASSACRE SUSPECT AS A SMALL TOWN HOPES FOR CLOSUREThe Muscatine Police Department is being assisted in the investigation by the Muscatine Fire Department, Muscatine County Sheriff's Office, Iowa State Patrol and the Iowa Division of Criminal Investigation.Kies called the killings an "act of evil" and said the community is mourning."Today, I simply do not have the words," Kies said. "This act of evil and what it has done to our community."The chief confirmed McFarland had a criminal record but declined to provide additional details.The investigation remains active as detectives continue processing multiple crime scenes and conducting witness interviews. Authorities are asking anyone with information about the shootings to contact the Muscatine Police Department's Major Crimes Unit.