“They had military-style weapons”
Were they really military-style or just fashionable with olive-drab accents?
Believe me, they were very bad news. The main thing the city can be faulted for is not stopping them sooner, although it's hard to see how they could have. I don't recall any talk of FBI or BATF involvement at all. It's like the City didn't want the feds in on the situation.