Local authorities have been trying to crack down on an Irish mob gang (IMG) that has been terrorizing several Oklahoma towns.

According to NewsOn6.com, the gang, which investigators say started in west Tulsa in the early 1990s, wears the color green, shamrocks, and Celtics jerseys, especially Larry Bird’s old No. 33.

The mob is involved in drug trafficking, robberies and home invasions. 

The Tulsa Police Department said that many of the mob members don’t just sell drugs, they also do drugs.

"They get strung out on meth and heroin and are constantly doing burglaries, stolen property, things like that,” TPD Organized Gang Unit Sgt. Sean Larkin said.

The Irish mob has been reported in 13 locations within the U.S. Five of them were in Oklahoma, including Tulsa, Catoosa, Norman, Oklahoma City, and the state prison system.

Police say the Irish mob is a big “white only” prison gang, and its members don’t get along with other white gangs.

In September, members of the IMG were involved in a turf war with the Universal Aryan Brotherhood at a private prison in Cushing. Four inmates were stabbed to death in the brawl, the Associated Press reports.