No motive for the attack was ever reported.
Cunningham was originally charged with second-degree attempted murder along with the assault count, and the case was presented to a grand jury and prosecuted by Livingston County District Attorney Gregory J. McCaffrey, who was on the scene shortly after the incident that evening.
Under the law, Cunningham faces between five and 25 years in state prison as a result of his conviction.
But officials say, based on his plea agreement with the Livingston County District Attorney s Office, the anticipated sentence is 20 years in prison, along with post-release supervision and a waiver of his right to appeal.