The silt evidence seems a bit muddled, if their theory held, they would find particles in the silt of their impact, and they haven’t found any.
Unless of course the Smoking Man actually has the particles and Mulder and Sculley are trying to find both.../s
So, efforts going back (braving the tens of billions of mosquitoes again! - will likely be focused on the lake area, so after next year they might find residue under the lake sediments.
Imagine a “slushy” comet - not a solid single rock or iron mass like a meteor/asteroid remnant. Then, near impact, it builds up enough air pressure/shock wave in front of itself to slow, heat up, and blow itself to bits: so the natural result is a slowing of the mass: not an acceleration away from the original mass like you would see from an internal explosion.
Random shock waves would not create all equal masses of pieces - so one large piece could get pushed up and away from the original trajectory (assume most the comet mass blew up at altitude at some flat (not vertical) angle to earth). Then you would see some large masses go sideways and impact at slower speeds.