KALAMAZOO, Mich. — The shootings came out of nowhere, one after the other, and with no apparent connection.

A woman was shot multiple times Saturday evening as she stood in the parking lot of her suburban townhouse complex. A few miles away, and a few hours later, a man and his son, who the authorities said was 17 or 18, were fatally shot outside a balloon-lined car dealership near a strip of fast-food restaurants. Minutes after that, along an interstate highway just outside Kalamazoo, four women were fatally shot, and a teenage girl gravely injured, as they sat in their cars outside a Cracker Barrel restaurant.

The authorities said a lone gunman, Jason Dalton, a driver for Uber, was responsible for the long, chaotic night of terror in this county, and investigators were looking into reports that he was ferrying passengers before the shooting began and perhaps even in between some of the sudden, random bursts.

One customer said Dalton took him on a harrowing ride around 4:30 p.m. Saturday, less than two hours before the shootings. Another said Dalton agreed to provide her a ride late Saturday, after the attacks were over.

The explosion of violence here left the authorities trying to piece together what might have prompted someone to roam in search of victims.

In all, six people were killed and two injured at three shooting scenes across Kalamazoo County, in southwest Michigan between Detroit and Chicago. The victims ranged in age from 14 to 74.

Dalton, 45, a former insurance company employee, was arrested without incident in the parking lot of a downtown Kalamazoo bar about six hours after the rampage began.

“There’s this sense of loss, there’s this anger, there’s fear, there’s all these emotions,’’ Jeffrey Getting, the Kalamazoo County prosecutor, said at a news conference early Sunday. “You put on top of that: How do you go and tell the families of these victims that they weren’t targeted for any reason than they were there to be a target?’’

Over the past year, the country has experienced a series of mass shootings — including ones at a church in Charleston, S.C.; at a community college in Oregon; and at a county government gathering in San Bernardino, Calif., which was later declared an act of terrorism. President Obama has repeatedly called for the nation to take steps to curb gun violence and carry out stricter background checks.

The authorities here did not immediately provide a motive for the rampage. “There is some information out there about what was happening’’ in the suspect’s life, Getting said. “You know, of course, it doesn’t come anywhere near to explain what he’s done.’’

Dalton, who was in custody Sunday and was expected to face formal charges as early as Monday, had no criminal record. Neighbors described him as quiet and polite, though he caught their attention when he occasionally shot a gun out the back door of the house he shared with his wife and two children. He had worked for Progressive Insurance until mid-2011.

According to one passenger, he started working as an Uber driver recently. The passenger, Sara Reynolds, 25, said Dalton drove her and a friend to a movie theater on Feb. 14.

An Uber official who declined to be identified because of the continuing investigation said Dalton had passed a company background check.

Joe Sullivan, chief security officer for Uber, said the company was “reaching out to police to help with their investigation in any way that we can.’’

“Our hearts and prayers are with the families of the victims of this devastating crime and those recovering from injuries,’’ Sullivan said.

Another Uber passenger, Matt Mellen, said in an interview with WWMT-TV that a driver who appeared to be Dalton picked him up late Saturday afternoon, and that the man had driven erratically, speeding through the streets, ignoring a stop sign, and swerving through traffic.

“He wouldn’t stop,’’ Mellen said. “He just kind of kept looking at me like, ‘Don’t you want to get to your friend’s house?’ and I’m like, ‘I want to get there alive.’?’’ Mellen said he had left the vehicle as quickly as he could.

He later told his fiancée what had happened, and she posted a warning on Facebook around 5:30 p.m. Saturday and said they had called 911. He said he also contacted Uber about the ride.

Shortly before 6 p.m., in a quiet suburban community northeast of Kalamazoo, shots rang out. James George, 17, said he had looked out the window to see a vehicle speeding away and a woman, wounded, sitting in the parking lot of the development. At least five bullet holes peppered the side of one rental townhouse. The woman, whom the authorities did not publicly identify, remained hospitalized Sunday evening.

About four hours later, at a Seelye Ford and Kia car dealership in Kalamazoo, there were more shots. Tyler Smith and his father, Smith, 53, were killed, the authorities said.

Then, in a matter of minutes, five others were shot as they sat in two cars — parked beside each other — at a Cracker Barrel in an isolated area near an exit ramp from an interstate highway. Bullet holes were left in a windshield and the car windows.

Four women died of multiple gunshot wounds, the medical examiner’s office said. They were identified as Mary Jo Nye, 60; Dorothy Brown, 74; Barbara Hawthorne, 68; and Mary Lou Nye, 62. A 14-year-old girl, part of the group, was in critical condition at a hospital.

More than two hours later, Dalton was arrested. Officers from the Department of Public Safety and deputies from the Kalamazoo Sheriff’s Department spotted the suspect’s car Sunday morning in downtown Kalamazoo and pulled him over and arrested him, the authorities said. No shots were fired.