Federal, state and local law enforcement took down a Newark-based narcotics ring Thursday.

Authorities say the group obtained and sold more than $20 million worth of prescription drugs, including the painkiller OxyContin. Attorney General Stuart Rabner says so far, the five ringleaders of the narcotics operation were arrested. Officials say the operation was violent, organized and methodical.

Mohamed Hassanain, of West Orange, the alleged ring leader, Doctor Mario Comesanas, of Livingston, who allegedly wrote phony prescriptions and Amhed Aly, a Union pharmacist who is accused of knowingly filling forged prescriptions, were among those arrested. The attorney general says the investigation is not over and he expects more arrests. Those arrested are charged with racketeering, possession of controlled substances, forgery and money laundering.