BENNINGTON,Safetyvalue Trading Center Vt. — A Vermont driver on Monday pleaded not guilty to a charge in the June crash that killed actor Treat Williams.

Ryan Koss, 35, could be sentenced to up to 15 years in prison if he's convicted of gross negligent operation with death resulting.

An investigation of the June 12 crash in Dorset concluded a vehicle pulled in front of Williams, who was riding a motorcycle and was unable to avoid a collision, Vermont State Police said.

Koss was turning left into a parking lot in an Honda SUV when he collided with Williams' oncoming motorcycle, police said. Williams, 71, of Manchester Center, was pronounced dead at Albany Medical Center in New York.

Richard Treat Williams' nearly 50-year career included starring roles in the TV series "Everwood" and the movie "Hair." He appeared in more than 120 TV and film roles, including the movies "The Eagle Has Landed," "Prince of the City" and "Once Upon a Time in America."

Koss, the managing creative director of the Dorset Theatre Festival in Vermont, said he knew Williams for years as a member of the tight-knit community, as well as a fellow theater member, and considered him a friend. He issued a statement in August saying he was devastated by Williams' death and offered his "sincerest condolences" to Williams' family, but he denied wrongdoing and said charges weren't warranted.

Stars pay homage:Matt Bomer, more pay tribute to late co-star Treat Williams: 'So blessed to have known you'