Atlanta and Denver had agents...
...also philly that i am personally aware of...
and they actually had a 'real' investigation going--interviews, witnesses, depositions, transcripts...
early summer '04 brian roberts (ceo comcast) was ready and trying to deal with frank, but frank wouldn't/couldn't and was stalling...
when roberts got the low-down skinny on the fed involvement, all efforts for the acquisition ceased immediately.
btw, the SEC is not the only federal agency involved in these investigations...
...which (as far as i am aware) are still open/ongoing investigations...