BERNARDSTON — Two men were arraigned on drug-related charges in Greenfield District Court Tuesday stemming from a traffic stop on Interstate 91 in December, during which state police found 90 bags of heroin.

Brian J. Smith, 37, of Lisbon, N.H., and Paul J. Valenza, 37, of Marshfield, Vt., were summoned to court on one count each of possession of a Class A drug after being pulled over for a license plate violation on I-91 in December. Valenza was also charged with a number plate violation.

Both men were released on personal recognizance following their arraignments.

State Police Trooper Jesse Gadarowski wrote in a report that he was monitoring traffic in the north lane of the highway during the early hours of Dec. 10 when he saw a Honda Civic pass with an illegible license plate. After catching up with the vehicle, he saw the back of the car was covered in dirt and road salt, making the plate impossible to read.

Gadarowski stopped the vehicle and the passenger, identified as Smith, got out to clean the plate. As he exited, Gadarowski wrote he observed a clear sandwich bag with one corner tied off on the floor of the vehicle, under the seat where Smith had been sitting. The trooper noted the bag was consistent with the packaging of illegal drugs.

While speaking with Smith and the driver, identified as Valenza, Gadarowski also observed an orange cap to a hypodermic syringe under the back of the passenger seat. He wrote in the report that both men’s pupils were extremely constricted and did not react normally to the light from his flashlight — both indicators of opiate use. Both admitted to using heroin in the past, but told Gadarowski they were clean.

Based on Gadarowski’s observations, state police conducted a search of the vehicle and found numerous empty wax paper bags with brown residue consistent with the packaging of heroin, as well as used and new hypodermic needles — one uncapped with blood still inside it. Troopers also located 20 wax paper bags containing a brown powder believed to be heroin under the driver’s seat cover, according to the report.

Valenza admitted they had driven to Springfield to buy heroin, and revealed where 70 more wax paper bags were hidden in the vehicle after Gadarowski pointed out it was unlikely they made the 6 ½-hour round trip from Vermont to only buy 20 bags of heroin, according to the report.

Both men were issued a summons. They are due back in court March 7 for a pretrial conference.