The cause of the deadly bus crash in Queens that left three people dead and 16 others injured remains under investigation Tuesday.

A fired MTA bus driver with a history of driving under the influence was behind the wheel of the speeding charter bus that struck a Q20 bus at Main Street and Northern Boulevard in Flushing around 6:15 a.m. Monday.

The driver of the charter bus, identified as 49-year-old Raymond Mong, died in the crash. Two others, a pedestrian walking to work and a passenger on the MTA bus, were also killed, while several were left in critical condition.

Henryk Wdowiak, 68, was walking to the 7 train on his way to work when he was fatally struck.

"He was a good man, a hard-working man," wife Halina Kurpiewska told Eyewitness News, speaking in Polish. "I am devastated."

Witnesses described a horrific scene.

"It was bad, it was really bad," Mike Ramos said. "I felt the vibrations shake my truck...I saw a guy with a cracked head, a cracked skull open. I saw guys bleeding all over the place...When I ran across the street, there was a woman pinned, screaming in the back of the city bus. I guess she was one of the pedestrians walking on the sidewalk."

Meanwhile, there are new calls for a New York City Council hearing to examine charter bus regulations following the crash. Council member Ydanis Rodriguez said the hearing should also look at redesigning the intersection to improve safety and reduce traffic. New York State Comptroller Scott Stringer said driver fatigue and rules for bus inspections must also be considered.