A Kalamazoo, Michigan man arrested on suspicion of killing six people this weekend was a driver-partner for Uber, the San Francisco-based company confirms. Furthermore, authorities are investigating unconfirmed reports that the suspect may have searched for and driven passengers during and after his alleged rampage, as the Associated Press writes for the Chronicle.

"We are horrified and heartbroken at the senseless violence in Kalamazoo, Michigan,” Joe Sullivan, Uber’s chief security officer, said in a statement on the company's website. “We have reached out to the police to help with their investigation in any way that we can.”

Jason Dalton, who was arrested in connection to the killings, is a former insurance adjuster with no criminal record. Nonetheless, he may have shown distressing signs of violence and menace before the murders started. As one previous passenger tells WWMT.com West Michigan, Dalton appeared upset and angry and drove erratically just six hours before his arrest.

“He wouldn’t stop," the passenger 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.' ... I’m upset because I tried contacting Uber after I had talked to the police saying that we needed to get this guy off the road.”

The passenger's fiancé also wrote to Facebook to complaining of Dalton's driving.

Another man claims to have been a passenger of Dalton's after the shootings had begun.
“My father mentioned from the back seat, you know, the situation with the shooter,” the man told 24 Hour News 8. “I kind of jokingly said to the driver, ‘You’re not the shooter, are you?’ He gave me some sort of a ‘no’ response… shook his head… I said, ‘Are you sure?’ And he said, ‘No, I’m not, I’m just tired... And we proceeded to have a pretty normal conversation after that.”

According to the Washington Post
, Kalamazoo Public Safety Chief Jeff Hadley calls the attacks “completely and totally random.”

The tragedy comes a week after Uber offered to settle a lawsuit by giving customers $28.5 million and changing the name of their "safe ride fee" to a "booking fee." That shift in language reflects criticism of Uber's background checks, which it calls industry-leading but do not require fingerprints as do taxi companies. Uber bans drivers from carrying firearms in their vehicles while driving for the company.

Those shot to death in Michigan were Mary Lou Nye, 63, Mary Jo Nye, 60, Dorothy Brown, 74, Barbara Hawthorne, 68, Richard Smith, 53, and his son Tyler Smith, 17. Two others were wounded. Mass Shooting Tracker puts the events as the 42nd such incident of the year so far.

Previously: Uber Offers To Pay $28.5 Million To Customers, Rename 'Safe Ride Fee' To Settle Lawsuits