I just searched Burdick in the CASO file, it didn't come up. Honestly, I haven't really looked much at these different sightings and where they were, but IIRC there different sightings reported, not all in the same spot, I think there was 2 spots along that highway, on either side of the river or dam or something, I'm not sure.
I thought Burdick just came forward recently, I don't recall his name being in the files.
ETA: here is his affidavit
http://www.stevenaverycase.org/wp-content/uploads/2018/07/Exhibits-21-30.pdf#page=75