Police investigators are still probing the events that led up to the tour bus crash that killed 15 passengers last Saturday morning on Interstate 95 near the Westchester County-Bronx border.

Officials have now revealed that World Wide Tours bus driver Ophadell Williams, 40, had a criminal record that involved serving time for manslaughter and grand larceny.

According to a recent statement that was released from New York State Governor Andrew M. Cuomo, "Given Ophadell Williams' criminal record and driving history, I have directed the New York state Inspector General to commence an immediate investigation into the circumstances surrounding how Mr. Williams was able to obtain and retain a commercial driver's license."

The tour bus was en route back to Chinatown from the famed Mohegan Sun casinos in Uncasville, Connecticut, when the bus was allegedly clipped by a tractor-trailer according to the police account given by Williams. Police were able to pinpoint the accused trucker but he however, vehemently denied Williams' story. The truck driver told investigators that he witnessed the bus slam into a pole that sheared it end to end. The nine men and six women who were killed received blunt trauma injuries.

A driver who was traveling in front of the tour bus told police that the vehicle in question was "all over the road."

After inspectors scrupulously examined the truck, they did not find any marks at all that could connect the vehicle with striking the bus.

Williams' fishy story sparked further investigation into his background. The Brooklyn-based bus driver's past revealed a Pandora's box of prior arrests. In 2003, Williams was charged with unlawful possession of radio devices, aggravated unlicensed operator and for driving with a suspended license. He has also been arrested for fare evasion in 1987, manslaughter in 1990 and grand larceny in 1997, according to records. In 1995, he was ticketed for driving without a license and using the alias Erik Williams. As a result, Williams' driver's license was suspended which meant he could not legally operate a motor vehicle in New York State.

Furthermore, according to federal records Williams' employer, World Wide Tours, was cited a total of 26 times over the last two years. Five of the violations were connected to drivers who operated while fatigued in the states of New Jersey, Pennsylvania and Connecticut.

Law enforcement officials are delving into Williams' last 72 hours before the bus crash which includes examining the casino's surveillance video.

We want to know what he ate, what he drank and how much he slept," National Transportation Safety Board vice chairman Christopher Hart told the Associated Press (AP). Reportedly the casino, which primarily caters to a huge Asian gambling population, has a lounge for bus drivers with beverages snacks and televisions, Mohegan Sun President Jeff Hartmann said. It is still not known whether Williams spent time in the lounge.

Williams, who was sustained minor injuries was released from the hospital Sunday.

There are no federal regulations that would prohibit states from issuing a license to a bus driver with a criminal record, Duane DeBruyne, a spokesman for the Federal Motor Carrier Safety Administration told the AP.

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