"It is the fact that the local PD came to the conclusion that GD (who's primary business is drug dealing and shooting each other over drug corners) would be behind some street level hustle"

Their major income is from drug trafficking but it isn't their primary activity. GDs are involved in a range of activities from extortion, gambling, prostitution, and white collar frauds. The Chicago GDs have renegades crew warring each other, but and the other 33 states it's All Is One in different cities. They still have meetings and social events, ex: In Hattiesburg there was a B.O.S weekend some weeks ago. Therefore these local police aren't wrong if they did the investigation.