SACO — Saco police, conducting an underage drinking detail outside the Hannaford supermarket on Main Street, instead charged three people with marijuana offenses.

The officers were conducting surveillance at the store at 7 p.m. Saturday, looking for people who are under 21 trying to get adults to buy alcohol for them, said Deputy Chief Jeff Holland.

They became suspicious of a group of people in a Subaru filled with smoke and could smell marijuana when they approached, he said. Police charged Jeffrey Bergeron, 23, of Biddeford with trafficking in marijuana and issued court summonses to Jacob Deschambeault, 28, and Paul Bolding, 36, on charges of possession of marijuana.