LAWRENCE, Mass. — Authorities say a state and federal investigation has led to the arrests of 12 people in connection with a heroin and fentanyl trafficking operation that brought drugs into multiple communities in Massachusetts.

Attorney General Maura Healey said Friday authorities seized about 900 grams of suspected heroin and the potent painkiller, along with $21,000, from Haverhill and Lawrence.

The operation brought the drugs into Lawrence, Haverhill, Lowell and Peabody. All of the suspects are from those cities.

The defendants will be arraigned Monday in Lawrence District Court on drug trafficking and conspiracy charges.

Healey says the state Department of Public Health estimates that 2,069 people died from opioid overdoses last year— the highest number ever recorded in the state.

The investigation is ongoing.