Revealing mistake: When the private eyes enter the mausoleum it is well lit from the studio lights when it should be pitch black as they enter.
Continuity mistake: Throughout most of the film it is night-time, but 3/4 of the way through a backdrop of the estate is dusk.
Other mistake: It is night-time when Dr. Tart (Conway) releases the 2nd dove out the window. Moments later we hear 2 gunshots and a plop sound of a dead bird. Which would be impossible as the shooter could not see a gray bird in the night sky.
Revealing mistake: When the private eyes are outside on the grounds there is loud thunder and lightning but it never rains.
