A tremendous amount of circumstantial evidence has been collected and scrutinized over the decades. Foot print castings which include dermal ridges, hair samples, blood and tissue samples, film (Patterson the best example), etc.
Blood and tissue samples have over the years been DNA tested, and are inconclusive. Several samples have been determined/identified as "unknown primate".
Realistically, the ONLY way to prove the existence of a currently unknown and undocumented North American primate/hominid will be for a dead body to be produced for scientific study.
