An armed man gunned down a new village police chief and then killed two employees in a nearby nursing home, where he later was found dead, a sheriff in Ohio said.
No nursing home residents were injured, nor were two hostages briefly held by the alleged gunman.
The murdered police chief, Steven Eric Disario, had headed the Kirkersville Police Department for only about three weeks, Licking County Sheriff Randy Thorp said.
Mr Disario was shot on a street near the Pine Kirk Care Centre, and the two female employees and the gunman were found dead inside, Mr Thorp said.
Authorities identified the gunman as Thomas Hartless, 43, of the nearby village of Utica.
The employees were Marlina Medrano, a nurse, and 48-year-old Cindy Krantz, a nurse's aide.
Mr Disario, 36, was a father of six children, with a seventh on the way, the sheriff said.
Flowers and flags appeared in an impromptu memorial outside the village police hall, located less than a block from the site of the shooting.
Mr Thorp called it a hard day for all.
"We've lost a police officer. It's just a tragic event," he said.
"I guess the only peace of mind is that the threat is over."
Mr Thorp gave the following timeline of events in the village of about 500 residents, roughly 25 miles east of Columbus.
The gunman was in a wooded area behind the nursing home when he encountered two passers-by, whom he temporarily took hostage.
Mr Disario, responding to a report of a man with a gun, apparently encountered the gunman in that area.
The chief's last radio communication said he had the man in sight.
When a shot was fired at the chief, the hostages escaped unharmed.
"We don't know the cause or the purpose or what drove this individual to do this," Mr Thorp said.
Responding officers found Mr Disario on the street and then investigated a report of a gunman at the nursing home, Mr Thorp said.
Some of the nursing home's 23 residents barricaded themselves during the shooting, but none of them was injured, he said.
All were relocated to other facilities until investigators were out of the nursing home.
Ohio attorney general Mike DeWine, who came to the scene, said search warrants had been executed on two vehicles owned by Hartless and at his home in Utica, about 30 miles away.
He later said Ms Medrano had a relationship with Hartless. Officials said they lived on the same street.
Mr Thorp said law enforcers were still working to determine what, if any, relationship the man had with the nursing home.
The facility is secure, and it's unclear how the gunman got in, he said.
The shooting closed down the main street in the village, which was flooded with police officers from several surrounding agencies and with ambulances.