An Uber driver who may have picked up fares during a weekend killing spree was headed to court Monday to face charges of murdering six people in the northern state of Michigan.
Kalamazoo County Prosecutor Jeff Getting said local law enforcement agencies were still assessing all the crimes 45-year-old Jason Brian Dalton will be charged with at an arraignment later in the day.
"I anticipate out of that review will come six counts of murder, two counts of assault with intent to commit murder, and eight charges of what we call felony firearm, using a firearm during the commission of a felony," Getting told CNN on Monday.
"Murder charges carry life in prison without the possibility of parole. The others, life sentence with parole."
Uber confirmed that Dalton was a driver for the ride-sharing company, adding he had passed a background check and had no criminal record.
"We have reached out to the police to help with their investigation in any way that we can," Uber's chief security officer, Joe Sullivan, said Sunday in a statement.
Uber's tracking system would show the location of Dalton's vehicle during the chain of shootings Saturday night that left six people dead and two seriously wounded at three different locations, officials said.
A woman was seriously wounded outside an apartment complex, two people were killed at a car dealership, and four more were shot dead at a restaurant, where a 14-year-old girl was also seriously wounded.
Kalamazoo's public security chief, Jeffrey Hadley, said police were looking into reports Dalton picked up fares between shootings.
"I think as soon as we are able to latch on to the information in terms of his whereabouts in between the first and second shooting and second shooting and third shooting we will certainly understand where he traveled to and maybe lead us to other sources of information," Hadley said in a CNN interview.
One passenger has described being taken on a wild ride by Dalton a couple of hours before the rampage began.
"We were driving through medians, driving through the lawn, speeding along and when we came to a stop, I jumped out the car and ran away," Matt Mellen told CBS affiliate WWMT.
Mellen said he escaped at 4:30 pm, and called the emergency phone number 911. He told his fiancee what had happened and she posted Dalton's picture on Facebook as a warning to others.
Meanwhile, investigators were still trying to establish a motive for the killings.
"That is probably the million dollar question: 'Why would this individual do this?'," said Hadley.
Hadley described Dalton, a former insurance adjuster, as "an average Joe" who had no criminal record and had not come to the attention of law enforcement before the murders.
The New York Times said neighbors described him as quiet and polite, but that he occasionally fired a gun outside the back door of the house he shared with his wife and two children, ages 10 and 15.
The shootings appeared to be random, with people being cut down for no reason.
The first victim Saturday night was a woman who was with her three children outside an apartment complex at 6:00 pm when she was shot, Getting said.
She was seriously wounded but is expected to survive.
The gunman next struck at 10:00 pm, killing an 18-year-old boy and an adult male at a car dealership, according to Getting. Michigan Governor Rick Snyder said the victims were father and son.
The last and deadliest shooting came 10 to 15 minutes later at the Cracker Barrel restaurant where four more people were killed, according to Getting.
Security video at the dealership and the restaurant helped police identify the shooter's car, and Dalton was arrested at about 12:40 am Sunday when a sheriff's deputy saw his car leaving a local bar in downtown Kalamazoo.
Police seized a semi-automatic handgun and "additional evidence" from the car, the prosecutor added.
The state governor ordered flags lowered for six days starting Monday in honor of each of those killed, and met with relatives of hospitalized victims.
The Kalamazoo killings were the latest in a string of US mass shootings that include the December 2 massacre in San Bernardino, California that left 14 people dead, and the December 14, 2012 Sandy Hook school massacre that killed 26, including 20 children.
Gun violence claims the lives of about 30,000 Americans every year and mass shootings -- rare in most countries -- have been on the rise.