CHICAGO — A jury in Chicago has convicted six reputed leaders of the Black Souls street gang on charges they used extreme violence to solidify their drug-trafficking operations on the city’s West Side.

Jurors returned with verdicts Saturday in the first racketeering case to go to trial under a 2012 Illinois law designed to improve prosecutors’ ability to convict gang members.

Cook County State’s Attorney Kimberly Foxx heralded the verdicts, saying the Black Souls had “terrorized” the neighborhoods in which they dealt drugs for more than 10 years.

Each defendant faces up to life in prison for racketeering and drug conspiracy. Other co-defendants pleaded guilty earlier.

The presiding judge dismissed five deliberating jurors and replaced them with alternates. A defense attorney suggested that and other issues could be grounds for an appeal.