Sign up for our COVID-19 newsletter to stay up-to-date on the latest coronavirus news throughout New York A Patchogue man has admitted to driving while high on drugs when he caused a crash that killed an 82-year-old man in Sayville two years ago—after prosecutors dropped a murder charge.Thomas Herman pleaded guilty Friday at Suffolk County court to first-degree manslaughter. A grand jury had indicted him on charges of second-degree murder by depraved indifference, vehicular homicide and other crimes. But, Suffolk County District Attorney Tom Spota said prosecutors would likely be unable to convict him of murder after a convicted drunk driver who killed a teenager was acquitted of murder in a similar case in November.“Mr. Herman’s admission of guilt to this terrible crime means he’ll spend more than two decades in an upstate prison, and he won’t see the parole board until the year 2032,” Spota said.Authorities have said the 47-year-old man was driving his Chevrolet Trailblazer westbound on Main Street, when he struck five vehicles and then simultaneously hit a westbound Honda Accord and an eastbound Hyundai Elantra on Jan. 13, 2013.The driver of the last car he hit, Sam Longo of West Islip, died in the crash. His passenger, 79-year old Agnes Gilbert of Oakdale, was critically injured.Herman was high on PCP, Morphine and other drugs at the time, authorities have said.Spota cited the verdict in the case of Michael Grasing, who was found not guilty of murder but was convicted of vehicular homicide, manslaughter, leaving the scene of an accident, driving while intoxicated, failure to stay in a designated lane and speeding. In that case, Grasing killed an 18-year-old woman when he sped down Montauk Highway in Lindenhurst on June 24, 2012.Judge Mark Cohen is expected to sentence Herman to 21 years in prison on May 15.