HOLYOKE - Two Hartford men were driving northbound on I-91 Sunday afternoon with 500 bags of heroin when they were pulled over for a lane violation, according to state police.

The incident took place at 4:54 p.m. just south of Exit 16. The driver of the car was Aaron Diaz, 22, of 51 Campfield St., Hartford, and the passenger was Steven Pedraza, 22, of 91 Spring St., Hartford, said State Trooper Thomas Moriarty.

When police realized that Diaz was unlicensed, they asked the men to get out of their Jeep Cherokee. The trooper then noticed a large bulge in Diaz's jeans, and he said he had $2,500 in cash for a shopping trip to the mall, Moriarty said.

Diaz tensed up and started struggling with a trooper, then broke free and ran northward in the breakdown lane, dropping cash as he ran, Moriarty said. Diaz jumped over a guardrail and ran down an embankment and into the woods east of I-91 while Pedraza stayed with the trooper, he said.

Diaz dropped a large plastic bag in the woods, which troopers recovered and found to contain 500 small bags of heroin, he said. He also possessed $1,690 in cash, which troopers also recovered along I-91 and in the woods, he said.

Canine and helicopter assistance was called in. Diaz was located at 6:45 p.m. while walking on Hillside Avenue in Holyoke, and was brought to Northampton for booking. Diaz and Pedraza were held overnight and will be arraigned today in Holyoke District Court, Moriarty said.

Diaz is charged with trafficking, possession of a Class A drug, using a motor vehicle without authority, assault and battery on a police officer, resisting arrest and a right lane violation, Moriarty said. Pedraza faces lesser charges of being knowingly present in a trafficking situation, he said.