LITTLE ROCK — Sixty-one people are named in federal indictments unsealed Wednesday in an investigation into alleged drug trafficking by gangs in central Arkansas, according to a news release from Patrick Harris, acting U.S. attorney for the Eastern District of Arkansas.

Harris said federal, state and local law enforcement officers arrested 25 defendants early Wednesday. They joined 27 people who already were in custody on other charges, leaving nine of the people named in the indictments who remained at large.

An 18-month investigation by the FBI and the Little Rock and North Little Rock police departments into alleged gang activity led to the indictments.

During the investigation, agents seized, in searches or controlled buys, more than 2 kilograms of cocaine, 1 kilogram of heroin, more than 1 pound each of crack cocaine and methamphetamine and eight ounces of fentanyl. Agents also seized 25 guns and about $241,000 in alleged drug proceeds.

Eight indictments were unsealed Wednesday, the largest of which names 33 defendants who face 67 counts alleging heroin and cocaine conspiracies, both allegedly headed by Aaron “Black” Clark, 33, of Little Rock.

Other indictments allege cocaine and crack cocaine conspiracies and contain multiple methamphetamine, fentanyl, heroin, cocaine and crack cocaine possession and distribution charges, as well as multiple gun charges.

The defendants arrested Wednesday are scheduled to make initial appearances and enter pleas in U.S. District Court in Little Rock on Friday. Those who were already in custody will have court appearances on May 31.