Hmmm.... zoo-keepers should be considered reliable witnesses in this situation, however:
1. Based solely on her description, I would dismiss the claim of it being a panther, because we are poor judges of size (and indeed, estimating anything - weight, numbers in a crowd, height etc) and it is probably just a large feral cat
2. But, Chris said he saw the footprints and thinks it really is a black panther (jaguar or leopard or 60's activist

?). It becomes quite easy from here: surely he can take some photos and send them to experts for identification? (I assume, of course, that 'panther' paw-prints are distinguishable from domestic cat prints.)