Three people were arrested Monday in Hancock County in connection with what police are describing as a significant heroin trafficking operation that took a year to investigate.

Officers seized a “substantial amount of the drug, along with processed marijuana, guns and money,” said Peter Arno, commander of the Maine Drug Enforcement Agency, and Hancock County Sheriff Scott Kane in a joint press release. “The arrests disturb a significant source of the heroin being distributed within western Hancock County.”

Drug agents and deputies stopped a vehicle on Route 1 in Orland on Monday and arrested Paul Chiumiento, 32, of Orland and Aaron Carter, 40, of Sedgewick. Police say both men were in possession of heroin.

Agents and deputies then went to Chiumiento’s home, where he lives with his girlfriend, Hyacinthe Baril, 35. Police searched the home and seized 400 grams of heroin along with 22 pounds of marijuana, 750 Oxycodone pills, over a dozen firearms and $40,000 in cash. The drugs alone had an estimated street value of $153,000, police said.

A 2012 Mercedes SUV and a 2015 GMC pickup truck were also seized from Chiumiento.

He and Baril were charged with aggravated trafficking in heroin. His bail was set at $200,000 cash while her bail is $100,000 cash.

Carter was charged with conspiracy to traffic in heroin. His bail was set at $75,000 cash.

All three are being held in the Hancock County Jail.