TLDR: These official have only talked with other officials, who didn't give them access to high security areas. Probably just trolled the guys to get them to go away.
The official has never seen anything, but derives his knowledge from second hand interviews with other officials. A congressman cited in the article swaps between outlandish claims in front of the media of witnessing alien technology hidden by US agencies first hand to making minimal claims under oath and finally confessing that he never witnessed anything first hand.
In summary: no aliens anywhere