Treat Williams' cause of death revealed as 'severe trauma and blood loss' following fatal motorcycle crash in June

• Treat Williams died in June after being involved in a serious motorcycle crash.
• The 71-year-old actor's cause of death has been revealed as "severe trauma and blood loss."

Treat Williams died from "severe trauma and blood loss" following a motorcycle crash in June, Vermont State Police said Tuesday.

The actor, best known for his roles in "Hair" and "Everwood," died on June 12 after a Honda SUV collided with his motorcycle in the town of Vermont. Williams was airlifted to Albany Medical Center in Albany, New York, where he was pronounced dead.

In a news release Tuesday, Vermont police also said the driver of the Honda vehicle, Ryan Koss, 35, has been charged with "grossly negligent" driving. He was processed and released on the charge Tuesday evening, and will be arraigned on September 25.

The state police department said in June that Koss "attempted to turn left into a parking lot," which is when he crossed Williams' path. According to a news release issued at the time, the star was "unable to avoid a collision and was thrown from his motorcycle."

Williams was best known for playing hippie George Berger in the 1979 musical, "Hair," which follows a US Army draftee who is shown an alternative way of living by Williams' character. He also had a recurring role in "Chicago Fire" as former firefighter Benny Severide, the father of the main character, Kelly Severide (Taylor Kinney).

In June, Williams' longtime agent Barry McPherson told People: "I'm just devastated. He was the nicest guy. He was so talented."

"Filmmakers loved him. He's been the heart of Hollywood since the late 1970s. He was really proud of his performance this year," McPherson added. "He's been so happy with the work that I got him. He's had a balanced career."