GRAFTON (CBS) – A Hyde Park man is facing heroin trafficking charges after a traffic stop on the Mass. Pike in Grafton.

State Police say on Thursday afternoon, Sgt. Michael Richards was driving eastbound when he saw a brown Jeep Grand Cherokee speeding in the left lane.

When the trooper pulled over the SUV, he reported that the driver, Ronnie L Searcy, 51, and the passenger gave conflicting stories about where they were headed.

Sgt. Richards called in a drug sniffing K-9. The dog sniffed out a bag containing three large plastic wrapped cylinders that State Police say was filled with 3 kilograms of heroin. State Police did not say what they estimate the street value of that heroin to be. Using calculations from a recent drug bust in Rhode Island would put the value of this bust as high as $700,000.

Searcy was charged with heroin trafficking as well as speeding and failure to keep right.

He was held on $340,000 bail.