NEW YORK - A tour bus driver who prosecutors said was all but asleep at the wheel was acquitted Friday of manslaughter and negligent homicide in a crash last year that killed 15 gamblers on their way from a Connecticut casino to New York City.

Ophadell Williams was found guilty on one count of aggravated unlicensed operation of a motor vehicle. Williams wept and covered his face with his hands as the verdict was read. On the count of which he was found guilty, the judge sentenced him to 30 days in prison, which he has served. He also was ordered to pay a fee of $500.

Williams argued that he had been awake and alert. He said a tractor-trailer cut him off, causing him to swerve and hit a guardrail. But investigators could find no indication that had occurred.

His lawyer had said he was wracked with guilt over the crash - but not guilty of manslaughter.

"It happened as a motor vehicle accident, not as some crime," said Williams' lawyer, Patrick Bruno.

The defendant left the courthouse without speaking. Bruno said Williams just wanted to go home and relax with his family.

"He had great faith that he would be vindicated," Bruno said outside court. "He said, 'Thank you so much. I knew that they would do the right thing.' ... His wife and sister hugged and kissed me and said, 'Thank you. This is the greatest Christmas and birthday gift of all.' "

Bruno said the verdict is a major case for this generation.

"It's saying that if you are going to try and make fatigue - sleepiness - a criminal legal issue in a motor vehicle accident, you have a lot, lot more to prove," he said.

Florence Wong, who lost her father, Don Lee, 76, told reporters she still believes Williams is responsible for the deaths. "I do not agree with the jury, but I respect their decision because they did look at the evidence and they came out with a verdict," she said.

Prosecutor Garry Wiel called the verdict a disappointment.

"I believe that we had enough evidence to show the jury that he should be held criminally responsible," Wiel said. He had alleged Williams was so sleep-deprived from working another job during the day that it affected his reflexes.

The March 12, 2011, crash happened on Interstate 95 at daybreak as Williams was ferrying a busload of gamblers to Manhattan's Chinatown from the Mohegan Sun casino in Uncasville, Conn.