WILLIAMSTOWN - Police arrested four people Tuesday night after a routine traffic stop turned up 74 individual packets of heroin in a vehicle driven by Willie Gary, 21, of Brooklyn, N.Y.

According to a statement released by the Williamstown Police Department on Wednesday, Officer Kevin Garner stopped the 2004 Mazda at approximately 2:15 a.m. The car was driving south on North Street in the area of Field Park and was stopped for traveling in the wrong lane around the cement barrier at the rotary, police said.

Garner discovered that Gary was driving without a valid driver's license. Further investigation turned up the drugs, police said, and Gary and the vehicle's three passengers - Brooke Simmons, 26, of Cohoes, N.Y., Erik Thomas, 27, of Troy, N.Y., and  Lernal Foster, 21 - were charged with illegal possession of a Class A substance with intent to distribute and conspiracy to violate drug laws.