I went to the "UFO Truth" event in Port Townsend, WA a couple weeks ago and it was mostly unremarkable except for Peter Davenport's (of the National UFO Reporting Center) presentation.
At the end of it he recalled the death of Todd Sees in PA but added something I'd never head before (this may have been the first time he told it), and I found interesting.
He said, a little more than a decade ago, the FBI asked to interview him and he spoke to them for about 4 hours during which time they asked him about the contents of the NUFORC files. (This fact was corroborated by the Seattle Weekly in an article they did about Davenport a few weeks ago. That is, they verified that the agents Davenport identified were employed by the FBI and the FBI did confirm that those agents did speak to Davenport on the dates he indicated and at their instigation, though they wouldn't confirm the details of that conversation.)
At the end of the conversation - and this is what I found interesting - the FBI asked if he had ever received a report that would indicate to him if "any agency of the United States government were engaged in extra-constitutional activities" (to which he replied, no).
I remain undecided on the alien visitation question and the wording of this question puts me further in the camp of belief that sightings/abductions are phenomenon created by humans acting outside or above the law and that, at least some segment, of the law enforcement apparatus is investigating this possibility.
[For those not familiar with Todd Sees, basically he was a guy in P.A. who went ATV'ing one day in 2003 and never returned. This coincided with neighbors reporting lights in the sky. His ATV was discovered with his clothes neatly folded and laying on top of it. After a 3 day search by 200 volunteers someone saw a severely mutilated human corpse in a tree. The local police, instead of removing the corpse, called the FBI who removed it and then, a few days later, returned it to the family in a lead coffin that had been bolted shut and welded at the seams. (Davenport says he thinks there was probably just dead weight in the coffin and no actual remains.) They listed the cause of death as a cocaine overdose.]