YARMOUTH, Maine >> Four people were fatally shot at a house in Maine on Tuesday shortly before gunfire wounded three others on a busy highway, in a pair of crimes that are linked, authorities said. Hours later, a man was charged with murder.

Police closed a portion of the interstate highway and residents and businesses in the area were ordered to shelter in place for about 90 minutes before authorities determined there was no threat to the general public.

The shootings are among a spate of recent mass killings that have shaken communities both large and small, including a Christian elementary school in Nashville, Tennessee; a bank in Louisville, Kentucky and a Sweet 16 party in a small city in Alabama.

In Maine, police charged Joseph Eaton, 34, of Bowdoin, with four counts of murder Tuesday evening but declined to discuss a possible motive for the shootings or identify the shooting victims. Eaton was expected to appear in court later this week.

The crimes began in rural Bowdoin, where the bodies were found, and continued with gunfire 25 miles (40 kilometers) to the south on Interstate 295 in Yarmouth, police said. One of the three highway victims was critically wounded, police said.

Law enforcement officers, some carrying long rifles, could be seen canvassing areas near the highway after the shootings. At one point, heavily armed officers at an off-ramp peered inside the trunk of a car that had apparent bullet holes in the windshield. Police said a person of interest was detained, and witnesses saw one person in handcuffs.

In Bowdoin, a farming community with about 3,000 residents, yellow crime tape hung where the shootings took place, in a home flanked by woods at the end of a long, gravel driveway. About 10 marked and unmarked law enforcement vehicles and a crime scene van were parked outside, and investigators moved about the scene.

At one point, a woman spoke to police outside the house before dropping to her knees and sobbing. Later, hearses were seen leaving from the driveway.

The town of Bowdoin has no affiliation with Bowdoin College, which is located about 10 miles (16 kilometers) away, in the town of Brunswick.

Maine Gov. Janet Mills tweeted her concern for the “families, friends and loved ones of those impacted by this tragedy.” She said she was praying for the injured.

“Like people across Maine, I am shocked and deeply saddened. Acts of violence like we experienced today shake our state and our communities to the core,” she said.

In Yarmouth, traffic backed up on the interstate as police shut down the southbound lanes. The highway reopened later Tuesday, with the exception of one exit where the police were inspecting the car.

Employees at Water Treatment Equipment Inc., a business near the highway, locked the doors and pulled down the shades after being alerted to the lockdown, which lasted about an hour and a half, manager Kim Snyder said. Workers saw cars backing up on the highway, along with police cars, ambulances and fire trucks.

“It definitely shifted the day, and the worry kicked in,” she said. “They hadn’t caught the active shooter. We didn’t know what was going on.”

Lenora Felker, who works near the highway at Rosemont Market and Bakery, said she sensed something was afoot when people started streaming in, saying the highway was closed, followed by dozens of law enforcement officers who descended on the area.

Officers went business to business asking if they had seen “anyone that was wet and muddy fleeing,” Felker said. But she knew all the customers and didn’t see anything unusual, she said.