One possible answer to all the commenters asking, "Why isn't anyone doing anything?" may be that there has been an ongoing investigation into Ali and his buddies' other activities. If the FBI or DEA have an informant working in or near the gang, they may hold off until all their ducks in a row, and then swoop in on everyone. They may order the locals to be patient and tread water on the murder.
I've seen news stories like this about complaints from neighbors in a city "hood" that cops are doing nothing about drug sales and violent threats, until a couple of months later when they show up in force with a fistful of arrest warrants and clean house.
Just a thought . . . .
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.