HAWTHORNE, N.Y. — Investigators were trying to determine if criminal wrongdoing led to the high-speed crash of a tour bus that overturned on Interstate 95 as it was returning from an overnight casino trip, slamming into a pole that nearly sheared off its roof and killing 14 passengers.

Police said they were trying to verify the bus driver's assertion that he lost control trying to avoid a swerving tractor-trailer and looking into his activities before the accident. The bus had just reached the outskirts of New York City on a journey from the Mohegan Sun casino in Connecticut when the crash occurred.

As many as 20 passengers were treated at area hospitals. Eight were in serious condition, according to police. Several were in surgery later in the day.

The crash happened at 5:35 a.m., with some of the 31 passengers still asleep. The bus scraped along the guard rail for 300 feet, toppled and crashed into the support pole for a highway sign indicating the exit for the Hutchinson Parkway.

The pole knifed through the bus front to back along the window line, peeling the roof off all the way to the back tires. Most people aboard were hurled to the front of the bus on impact, said Chief Edward Kilduff of the Fire Department of New York.

The southbound lanes of the highway were closed for hours while emergency workers tended to survivors and removed bodies.

State police Maj. Micheal Kopy said at a news conference Saturday night in Hawthorne, N.Y., that the crash was being handled "as if it is a criminal investigation."

"It will take a long period of time to determine what, if any, criminal acts may have occurred here," he said.

Kopy said police had received reports from witnesses that the bus driver had been speeding on the Interstate, where the limit is 55 mph.

He identified the driver as Ophadel Williams, 40, of Brooklyn, N.Y., whom he said was taken to a hospital with non-life-threatening injuries. Kopy said blood had been drawn from the driver for analysis and that state police were working with authorities in Connecticut and Mohegan Sun officials to determine what the driver's activities were before the accident.

"At this point it appears that the operator lost control of the vehicle for what is as yet an undetermined reason," Kopy said.

He declined to identify the passengers or to describe their injuries. "The pole did go through the top half of the bus," he said.

Chung Ninh, 59, told The New York Times and NY1 News that he had been asleep in his seat, then suddenly found himself hanging upside-down from his seat belt, surrounded by the dead and screaming. One man bled from a severed arm.

Ninh said when he tried to help one bloodied woman, the driver told him to stop, because she was dead. "Forget this one. Help another one," he said the driver told him. He said he and other passengers who were able climbed out through a skylight.

Passenger Jose Hernandez, 49, said he also was asleep at the time of the crash.

"We tried to help people, but there was twisted metal in the way," Hernandez told the Times.

New York Police Commissioner Raymond Kelly said earlier Saturday that police were looking for the tractor-trailer, which did not stop after the crash. He said the truck was in a lane to the bus' left, although it was unclear whether the two vehicles touched.

State police said later they were interviewing the driver of a tractor-trailer that was in the area at the time of the crash. They said the trailer had been located on Long Island and the tractor was found in Westchester County. Both were being inspected in Farmingdale, on Long Island, to determine if they may have clipped the bus.

The bus, a 1999 Prevost, was being inspected at state police barracks. Video from a camera on the bus had been obtained by authorities but not yet analyzed, Kopy said.

He said investigators were trying to determine the exact speed the bus was traveling before the crash. A device that can record such information, similar to a flight data recorder on an airplane, was expected to be examined overnight.

Limo driver Homer Martinez happened on the scene moments after the wreck and saw other drivers sprinting from their cars to assist the injured.

"People were saying, `Oh my God. Oh my God,' holding their hands on their heads," Martinez said. "I saw people telling other people not to go there, `You don't want to see this.'"

Capt. Matthew Galvin of the NYPD's Emergency Service Unit was one of the first rescuers on the scene. He said when officers clambered into the wreckage, they found "bodies everywhere."

"People were moaning and screaming for help," he said. Some of the dead were tangled up with the living.

Though dazed, about seven people were able to walk away from the wreck on their own, he said. Galvin said that in his 22 years on the job, "It's probably the worst accident I've ever seen in terms of the human toll."

The wreck also closed the northbound side of the highway, but those lanes were open again by midmorning.

The National Transportation Safety Board sent a team of investigators.

Christopher Hart, the vice chairman of the NTSB, said the team would be looking at the motor carrier's safety programs, including those involving driver fatigue, as well as highway design and the bus itself. He said that part of the investigation could take several days.

Many of the passengers on the bus were Chinatown residents. They ranged in age from 20 to 50, officials said.

Fifteen were being treated at Jacobi Medical Center in the Bronx. A hospital spokeswoman, Barbara DeIorio, said some injuries were serious but had no immediate information on how many were gravely hurt. Five more were taken to St. Barnabas Hospital, where two were on life support, breathing with the assistance of machines.

"We've had skull fractures, rib fractures ... internal bleeding, we've had lung contusions," said Dr. Ernest Patti, senior attending physician at St. Barnabas.

The bus driver was "awake and conscious," Patti said.

World Wide Travel of Greater New York, the operator of the bus, said it in a statement that the company was "heartbroken" and cooperating with investigators.

"We are a family-owned company and realize words cannot begin to express our sorrow to the families of those who lost their lives or were injured in this tragic accident. Our thoughts and prayers are with them," it said.

Federal Motor Carrier Safety Administration records listed World Wide Travel as having at least two other accidents in which people were injured in the past 24 months. The agency flagged the company for possible extra scrutiny due to violations involving driver fatigue regulations.

The bus was one of scores that travel daily between Chinatown, in Manhattan, and the Foxwoods and Mohegan Sun casinos in southeastern Connecticut.

Mohegan Sun, in Uncasville, Conn., has estimated a fifth of its business comes from Asian spending and caters to Chinese-American gamblers. Its website has a Chinese-language section offering gaming and bus promotions.