ObscureHollywood.net’s review published on Letterboxd:
In the 1890’s, Vincent Price, an inventor of fantastic magic apparatuses, wants to perform with his own devices. Producer Donald Randolph stops his act. Price has a contract to deliver all his inventions to Randolph. They argue and a maddened Price murders Randolph with his latest magic device, a buzz saw. Price gets rid of the body in the convenient bonfire celebrating the local college’s football victory. Price, a master of disguise, masquerades as Randolph. Randolph’s greedy wife, Eva Gabor, discovers the impersonation, and he kills her too. Price’s latest invention is an incinerator, the magician’s assistant is dropped out the bottom before the fire is ignited. John Emory, a famous magician, expects Price to give him the device. Price gives him a first hand view of it. Price impersonates Emory and takes over his act.
A detective, investigating Gabor’s murder and the disappearance of Randolph, utilizes the "modern" technique of comparing fingerprints to associate Price with the crimes.
The Mad Magician is a follow-up to House of Wax (1953), similar in plot and use of 3D effects. Once again, Vincent Price is an artist who is deprived of his creations by greedy associates. His maddened revenge is horrific.