Question?? Why would FBI, Homeland Security and LAPD be doing a raid together?

Does anybody have an idea as to why the FBI, Homeland Security and LAPD would be conducting a large scale raid together? This event came complete with the big LAPD battering ram, percussion grenades, rooftop snipers, helicopters and marked and unmarked vehicles.
This being Southern California, stuff happens all the time, but what got me is no news coverage, nada. The only reason I know about it is because my husband works down the street from where it happened yesterday and wasn't allowed to leave work.
So ATS'ers any ideas???

The LAPD would have been used because they had the battering ram and other equipment that the FBI doesn't keep handy. As well as for manpower. Homeland Security and the FBI frequently work together.