After a drunk reports seeing a weird creature in the river a number of people disappear. Investgators searching for illegal traps find that it is a giant monster that has devoured the missing people.
This is a classic of the B-Movie Sci Fi genre. Produced by Gene Corman and Directed by Bernard Kowalski
This 'Old Dark House' mystery in the vein of "The Cat And The Canary" tells the story of a scientist who dies and leaves his estate to his daughter. The estate will be divided amongst his other relatives if she doesn't live past a certain time. There is a plot to kill her, complicated by the 'ape' that the scientist performed experiments on.
Directed by Frank R Strayer (Vampire Bat, Condemned to Live, Murder at Midnight, etc.)