Nassau County officials say 15 suspected gang members and associates were arrested in connection with the sale of drugs and dogfighting in Roosevelt and Freeport.

The Nassau district attorney says the gang sold heroin laced with fentanyl, a powerful additive linked to dozens of fatal overdoses across Long Island. Fentanyl is a synthetic painkiller that is up to 100 times more potent than morphine.

Officials say 12 pitbulls, including two newborn pups, were rescued after allegedly being used in what they call a "heinous and barbaric dogfighting ring."

Investigators say the three ringleaders of the operation are Shaheem Allen, Kwame Reaux and Daquan McClean.

Detectives say search warrants were executed Wednesday morning in Freeport, Lynbrook, Baldwin and Roosevelt after a five-month investigation.

Some of the defendants pleaded not guilty during their arraignments Thursday. More will face a judge Friday.

Investigators say more arrests are expected in the case.