The tour bus driver who plowed into an MTA bus on Monday morning in Queens, killing himself and two others, was previously employed as an MTA bus driver—until he was fired for a DUI in Connecticut.

Raymond Mong, 49, was driving an empty bus for the Dahlia tour company on Northern Boulevard in Flushing shortly after 6 a.m. when he crashed into an MTA bus turning right from Main Street onto Northern Boulevard. The tour bus then careened into the corner of 136-04 Northern Boulevard. Security camera footage shows that Mong was driving the tour bus fast enough to cause the MTA bus to spin around nearly 180 degrees:

Mong was taken to Elmhurst General Hospital, where he was pronounced dead. A pedestrian, Henry Wdowiak, 68, died at the scene, while a passenger on the MTA bus, Gregory Liljefors, 55, died at NY Presbyterian Hospital. Sixteen other people were injured.

Connecticut State Police arrested Mong for an April 10th, 2015 incident in which he apparently drove onto an off-ramp from I-95 in New Haven and rear-ended a Chevy Tahoe with his Honda Acura. The Tahoe then hit a Volkswagen, whose driver, Alexandra Wynne, told the NY Post that she was at a stoplight and the Honda came "flying off the highway."

Wynne added, "His car was smoking after that, but he still backed up and then drove off on the highway... I was in shock. I was like, ‘Wow,’ I couldn’t believe he just drove off like that. And he was going fast. Highway cops ended up getting him a short time later."

When New Haven police caught up with Mong, they arrested him for drunk driving, leaving the scene, failure to have proper insurance, failure to drive at a reasonable distance and unsafe driving. Mong pleaded guilty, received 18 months probation and paid a $500 fine. He also surrendered his license, but the license was restored in early 2016, according to the Daily News.

Connecticut authorities notified the MTA about the arrest and the agency fired him. Mong had allegedly been trying to appeal his firing until this past summer.

The Dahlia Group has a checkered safety record. DNAinfo reports that in February 2016, a tour bus headed to Mohegan Sun rolled over on I-95, injuring dozens. One of the women injured, Olga Cortes, died of an embolism a month later. A Dahlia passenger, Randy Chan, is suing the company for a 2014 incident where he was shot by Connecticut State Police while Chan was trying to restrain another passenger, Hua Jian Ye, who was stabbing people on board.

Chan's lawyer Brittany Cates told DNAinfo, "Dahlia, it's our claim, didn't adequately protect its passengers. It made an unscheduled stop and let this unscreened passenger on the bus. The bus just pulled over and let him on where it had never done that before. They didn't evaluate or screen this passenger in any way. The driver wasn't trained to handle this in any way." She added that Chan is now in a wheelchair.

The police investigation into Tuesday's crash is ongoing. When police called Wdowiak's stepson about his death, Marcin Kurpiewska said, "I couldn’t expect this. My knees just gave out. I don’t think it’s sunk in yet ... Everybody loved him. He was one of those guys who would help without getting anything back."

Wynne, the victim in Mong's 2015 DUI, said, "I’m just shocked he was even allowed to drive a charter bus after that... That’s crazy. This tragedy could have all been prevented if this company took precautions by looking into who they were hiring."