ATLANTA --- When gang violence rose to an alarming high in the 1990s, Georgia legislators enacted a law that puts anyone convicted of gang-related crimes behind bars longer.

More than a decade later, the Georgia Street Gang Terrorism and Prevention Act is facing a challenge in the state Supreme Court from two groups of defendants who argue its definitions of gang members and crimes are so vague they ensnare the innocent.

In one case out of DeKalb County, attorneys for two defendants suspected as members of the notorious 18th Street gang and charged with murder and aggravated assault say the act's loose definition of a gang can apply to any group. They argue that if at least one member of the group has committed a crime it is defined as gang-related, they can all be prosecuted.

Additionally, someone charged under the act doesn't even have to consider themselves part of a group intent on breaking the law, according to the attorneys.

The second case involves a Bulloch County minor charged with battery, influencing a witness and two felony counts of street-gang activity under the act.

The boy's attorneys, who say he is not a gang member, argue that the act is unconstitutional because it contains no definition of what constitutes criminal gang activity.

Prosecutors in both cases say the law is not unconstitutional because it expressly excludes groups of three or more people who are not involved in criminal activity. The defendants in both cases were involved in at least one of the 10 forms of criminal gang activity the act spells out, the prosecutors argue.

The crimes listed under the act include any offense that involves violence or weapons. If the court declares the law unconstitutional, the effect of the opinion will depend on its breadth.

Law enforcement and prosecutors are monitoring the challenge. Maj. Mark Sizemore, of the Athens-Clarke Police Department, said the act isn't used often in his jurisdiction. But when it is, the charge usually piggybacks on serious firearms and assault charges against suspected gang members and keeps them off the street longer once convicted.

"It just adds time to their sentence," Maj. Sizemore said.

A conviction of the street gang activity charge can add five to 15 years to a prison sentence, and a fine up to $15,000.

Reach Jake Armstrong at (404) 589-8424 or jake.armstrong@morris.com.