They're listed in the Universal Horror history book, so... yeah.
I checked what the Universal Horrors history book had to say.
Secret of the Chateau (1934) is featured as "a creaky, dime-store whodunit that's all but forgotten today. It has little to distinguish it from the dozens of bottom-of-the-bill program mysteries that Hollywood studios cranked out with regularity in the '30s and '40s. Surprisingly, Universal took little advantage of the story's creepy country chateau setting and invested the film with precious few eerie effects. Chills and suspense are sacrificed for a succession of low-level gags. Judging from the film's advertising, however, one would get the impression Secret of the Chateau was a bonafide horror film, or at least a mystery thriller with strong horrific elements."
Life Returns (1935) "is a hopeless, exasperating conglomeration of events and images masquerading as a motion picture. For all the many years that it was out of circulation, fans knew only that Universal had released it and that the title and plotline suggested a borderline science fiction theme, and so hopes were raised. But the cold light of rediscovery revealed a depressingly cheap, incoherent flick built around a questionable scientific achievement."
Night Key (1937) is "neatly constructed to go from straight drama in its opening reels, tilting towards comedy in the mid-section and then winding down into a relatively tense gangster melodrama" [whose] "genre trappings are peripheral aside from some eye-catching scientific gizmos".
Strange Confession (1945) "is a straightforward, well-done B-grade domestic drama cum domestic tragedy"
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More importantly, none of the crime mysteries are featured in the Universal Horrors book proper, only in Appendix I - Exclusions, Borderline Inclusions, Odds and Ends
Universal Horrors Appendix I said:
The following is a series of capsule reviews of movies that some readers may have expected to find in the main section of this book—movies which include some minor horror, science fiction or fantasy elements, but not enough that we could bring ourselves to make them subjects of full writeups. Also included are movies that were either misleadingly advertised by Universal as horror movies upon their original release, and/or were later sold by TV stations in the false guise of horror movies.
These Appendix I mentions include
Inside Information (1939) ("strictly cops-and-robbers tomfoolery"),
The Lady in the Morgue (1938) ("inconsequential meller"),
Danger on the Air (1938) ("murder mystery romp"),
Mystery of the White Room (1939) ("barely passable whodunit"),
The Witness Vanishes (1939) ("a cozily familiar melodrama"),
The Man Who Cried Wolf (1937),
The Last Express (1938) and
Gambling Ship (1938).