BOSTON — A Braintree man and three others from Brockton were indicted in federal court in Boston this week in connection with an alleged conspiracy to distribute fentanyl and carfentanil in a dozen cities and towns south of, and including, Boston.

The indictment charges David Fernandes, 32, of Braintree; Rickey Depina, 31, of Brockton; Keanu Fernandes, 23, of Brockton and Viviana Fontes, 29, of Brockton with conspiracy to distribute and possess with intent to distribute fentanyl and carfentanil, two synthetic opioids.

According to the indictment, the defendants conspired to distribute the drugs from at least May through August of this year in Boston, Quincy, Braintree, Holbrook, Brockton, Abington, Whitman, Easton, West Bridgewater, Norton, Raynham and Fall River.

On Oct. 1, 2018, police stopped David Fernandes, Depina and Fontes while driving and found over 17 grams of fentanyl, about $1,750 and four cell phones, according to the indictment. While executing search warrants later that day, police found another $10,000.

Carfentanil is an analog of fentanyl that is about 10,000 times more potent than morphine and 100 times more potent than fentanyl. It is used commercially in tranquilizer darts for large mammals such as elk or elephants and can be lethal in a dose as small as 2 milligrams.