A Vineland man is in jail after he allegedly threatened a corrections officer with a knife.An off-duty corrections officer told State Police he saw a man slumped over inside his vehicle in the area of Ackley and Whitehead roads in Commercial Township around 5:25 p.m. Monday, according to information released Saturday.When the unnamed officer knocked on the window to see if the man needed help, Eric Winter exited his vehicle brandishing a knife, State Police said.He then fled.Trooper Anthony Maruca searched the area, and was able to find and stop Winter's vehicle, according to the report.While speaking with Winter, Maruca determined that he was under the influence of alcohol. Further investigation revealed that Winter was in illegal possession of a shotgun and rifle.Winter, 48, was charged with aggravated assault, possession of a weapon for unlawful purpose, unlawful possession of a weapon and driving under the influence. He was lodged in Cumberland County Jail pending a bail detention hearing.