Erie County District Attorney Michael J. Keane announces that Zachary P. Poisson, 34, of Depew, was sentenced this morning before State Supreme Court Justice Debra Givens. He received an indeterminate sentence of 2 ½ - 7 ½ years in prison. Additionally, his New York State driver’s license was permanently revoked.
On Monday, July 24, 2023, at approximately 5:30 a.m., the defendant, while under the influence of cocaine, was driving eastbound on Clinton Street in the Town of West Seneca when he crossed the center line, causing a head-on collision with a westbound vehicle. The driver of the other vehicle, 49-year-old David Sion of Eden, was pronounced dead at the scene.
Poisson pleaded guilty to one count of Manslaughter in the Second Degree (Class “C” felony), one count of Vehicular Manslaughter in the Second Degree (Class “D” felony), one count of Unauthorized Use of a Motor Vehicle in the Third Degree (Class “A” misdemeanor), two counts of Criminal Possession of a Controlled Substance in the Seventh Degree (Class “A” misdemeanors). He pleaded guilty to all counts in the indictment in March 2025.
DA Keane commends the West Seneca Police Department for their work in this investigation.
The case was prosecuted by Assistant District Attorneys Mitchell T. Schoellkopf of the Vehicular Crimes Bureau and Denise A. Herman of the Special Investigations and Prosecutions Bureau.