PITTSBURGH (KDKA) — The FBI said it took down multiple local gangs that were dealing large amounts of drugs.

Authorities announced the results of the 18-month investigation on Monday.

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(Photo Credit: KDKA)

Officials believe they put a massive dent in a local gang and drug activity after dismantling three violent gangs: Hustlas Don’t Sleep, Sco and Darkside Smashers 44.

Authorities said the gangs sold controlled substances primarily out of McKeesport, Turtle Creek, Wilkinsburg, and Monroeville.

After a six-month investigation by multiple agencies, 100 people are now indicted. Four hundred bricks of heroin laced with fentanyl and 119 guns were also seized.

Thirteen residents of Allegheny County and six associates were charged for violating federal narcotics and firearms laws, the Department of Justice announced.

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“These groups are responsible for homicides, shootings, robberies, assaults and other violent behavior that slows neighborhood revitalization in the city of Pittsburgh,” FBI Special Agent in Charge Robert Jones said.

The FBI Pittsburgh also said it is looking for Jason Jackson, who is part of Hustlas Don’t Sleep.

(Photo Credit: FBI Pittsburgh)

The Department of Justice said from September 2017 until November 2019, Hustlas Don’t Sleep conspired to possess with the intent to distribute and distributed 1 kilogram or more of heroin, 280 grams or more of crack cocaine, 100 grams or more of fentanyl and 400 grams of fentanyl.

One of the 13 people arrested, Duane Eugene Cash Jr., possessed with the intent to distribute 100 grams or more of an analog of fentanyl, 100 grams or more of heroin, 40 grams or more of fentanyl and 50 grams or more of methamphetamine, the Department of Justice announced.

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WATCH: KDKA’s Bob Allen reports live on the gang takedowns.