This Has Bugged Me For 40 Years- 50's movie

[Alicat848]

There was a movie, probably made in the 50s about aliens who take over bodies. I remember at the end, the hero and his female companion find the real people hanging in a cave. When they cut down the real people, the alien imposters start to ooze. I specifically remember the desk sergeant at the police station (an alien) starts to ooze from his sleeves. It's not "Not of this Earth' but the weird thing is that the animated series Martin Mysteries has an episode that sounds identical to this movie, only this wasn't animated. I don't know any of the actors, but the desk sergeant was bald and sort of looked like Tor Johnson from Plan 9.

Again, this has been bugging me for 40 years.
Help and thanks!!!!