It is not a rumor. I have seen this report:
pistol-training.com * Blog Archive * FBI & 9mm, and it has been confirmed by a couple of very knowledgeable people in the terminal ballistics/training field.
The 1076 was an utter failure for the Bureau. They had a lot of trouble with the platform (as did my agency when we had 1076s), and they were too big for the average plainclothes assignment. Remember that the FBI is not a police agency, so a uniformed duty size pistol is a fail.
There is a lot of information available about the lack of difference in performance between the common service calibers, and remember that a pistol is what you carry when you have no reason to expect a problem. Pistol rounds suck for fighting. A rifle is what one takes if a fight could be predicted.
If they are at a point at which the replacement of pistols is coming anyway, the savings in ammo cost is 20%+, with no change in ballistic performance, and better shooting performance by the agents. A win all the way around, if they get a platform that doesn't stink.