BOSTON — Federal authorities say a weekslong investigation into drug trafficking in Massachusetts has led to about 50 arrests and the seizure of large amounts of fentanyl, heroin and cocaine.

U.S. Attorney for Massachusetts Andrew Lelling said in a statement Monday the 10-week operation code named Devil’s Highway was a coordinated effort by federal, state and local partners to focus on drug distribution in Lawrence and between Lawrence and New Hampshire.

In addition to the 38 people facing federal drug offenses, at least a dozen more face state charges. Investigators also seized 31 pounds of fentanyl, 11 pounds of heroin, 64 pounds of cocaine, four firearms and body armor.

The majority of criminal charges resulted from weekly sweeps in Lawrence that targeted individuals distributing opioids.