State Police arrested a man driving eastbound on Interstate 84 in Sturbridge Sunday after troopers found 100 grams of heroin hidden inside a diaper, State Police said. Yefri Guerrero-Ramirez, 25, of Boston was originally stopped for excessive window tint, State Police said. A trooper determined that the driver “was not being truthful” and called for a narcotics-odor-detection dog, State Police said. The dog alerted officers to the front passenger side of the car. Officers searched the vehicle and found a baby bag on the floor near the passenger’s seat that contained a stash of heroin inside a diaper, State Police said. Officers also found a digital scale in the bag. Guerrero-Ramirez was taken to the State Police barracks in Sturbridge. He was charged with trafficking heroin and having obstructed, nontransparent windows and is being held on $1,000 bail, State Police said.