The butler didn't; The False Inspector Dew, by Peter Lovesey. New York: Pantheon. 251 pp. $12.50.; Uneasy Lies the Head, by Robert Tine. New York: The Viking Press. 177 pp. $12.95 .; The Man Who Liked Slow Tomatoes, by K. C. Constantine. Boston: David R. Godine. 177 pp. $12.95.; The Rocksburg Railroad Murders & The Blank Page, by K. C. Constantine. Afterword by Robin W. Winks. Boston: David R. Godine. 346 pp. $6.95 (paperback).; Stalking Horse, by Collin Wilcox. New York: Random House. 249 pp. $10.50.; An Uprush of Mayhem, by Jack S. Scott. New Haven: Ticknor & Fields. 184 pp. $10. 95.
Peter Lovesey performs sleight-of-hand with plots; as proof we have The False Inspector Dew, his ninth book, which is set in 1921 aboard the SS Mauretania.
The false inspector, Walter Baranov, is actually a dentist who embarks on the ocean liner to commit a crime, not to solve one. His wife, Lydia, is leaving him to seek her fortune in Hollywood, and Walter's plan is to murder her and take up with Alma Webster, a girl whose world view is shaped by romantic novels.
When another murder occurs on the Mauretania, Walter, traveling under the name of the great inspector, is called in on the case by the ship's captain. The false inspector stumbles upon a solution: The crime's roots are in the sinking of the Lusitania, and both Walter and the murderer were survivors of that disaster.
The plot of ''The False Inspector Dew'' is complicated and kinetic because Lovesey jumps from scene to scene - from card sharps, to millionaires, to young love, to activities on board, to detection.
Lovesey handles the large cast of characters adroitly, and the brevity of the scenes serves to push the action forward at an entertaining clip toward a very clever surprise ending.
Uneasy Lies the Head is Robert Tine's second book, and how appropriate is its title! The time is the late 1980s, and someone is trying to remove King George VII from the throne by framing him as England's latest Jack the Ripper.
Assigned to the case are an odd couple of detectives - young and ambitious Tony Pidgeon and old and easygoing Sam (Smudge) Huddles-ton - and because of the very artful nature of the conspiracy-frame, it appears to them that the King is guilty, indeed.
Of course he's not, and of course Tony and Smudge figure this out, but not without a great deal of friction between them, and not without difficulties on all other fronts. The King is appropriately grateful.
''Uneasy Lies the Head'' is an impressive book. Tine writes confidently and well. The plot is elaborate and suspenseful, but the book's strength lies in the nicely orchestrated contrapuntal relationship of Pidgeon and Huddleston.
Mario Balzic is the chief of police in Rocksburg, Pa., but he is not your usual cop, as he proves for the fifth time in print in K. C. Con-stantine's The Man Who Liked Slow Tomatoes.
Balzic is vaguely disreputable and profane, drinks too much, spends too little time at home; and his crime-solving methods are decidedly unorthodox - he's a character.
There's a murder in ''The Man Who Liked Slow Tomatoes,'' and Balzic earns his keep on that case, but Con-stantine's mysteries are at least as much about life in the small city of Rocksburg and about Balzic as a ''character'' as anything else. His book's frank, realistic dramas, full of vulgar street language that won't appeal to some readers, is similar in spirit to George V. Higgins's uncompromising exposes of Boston's underbelly.
Coincident with the publication of ''The Man Who Liked Slow Tomatoes,'' and possibly more palatable, is Godine's reprint of two earlier Balzic mysteries, The Rocksburg Railroad Murders and The Blank Page, in an attractive ''double detective'' format that also includes an afterword by Robin W. Winks, mystery reviewer for The New Republic and very likely this country's best mystery critic.
Two long-established policemen, one from England and one from San Francisco, are back at work. Collin Wilcox's Lieutenant Hastings appears in Stalking Horse to figure out who is sending death threats to Sen. Donald Ryan, one of the country's most powerful politicians. There is blackmail, and the turn of plot is too predictable. Better is Jack S. Scott's An Uprush of Mayhem, the seventh appearance for the boorish Detective Inspector Rosher. Scott can be very funny, but here he presses too hard; the plot could be more fluid, but still, the recently reinstated Rosher, described by his creator as ''strangely apelike,'' is worth keeping track of.