FOG ON THE TOLBIAC BRIDGE, by Leo Malet (Pan, $70). IN A PIG'S EYE, by Robert Campbell (Coronet, $79). THE SONG DOG, by James McClure (Faber and Faber, $76). CONTRARY to the popular adage, crime does pay, particularly for writers of this calibre. The first of these releases, ''a Nestor Burma mystery'', is an English translation of Leo Malet's 1956 novel set in Paris. Robert Campbell's offering is ''a Jimmy Flannery mystery'' set in modern-day grassroots-level Chicago, while The Song Dog is ''a Kramer and Zondi mystery'' set in South Africa about the time Nelson Mandela was on the loose before the start of his world attention-grabbing jail term. Malet based ''Dynamite'' Burma on the private eyes of 1930s American writers. Flannery is a conscience-driven Democrat, while James McClure's Tromp Kramer and Mickey Zondi are policemen in what is probably a more politically correct portrayal of white and black fighting crime. Malet mimics the spare style of his mentors but invests his private detective with Gallic charm, softening the gruffer hard-bitten nature of his American cousins. Burma receives a blast from the past in the form of a note from a hospital patient, who claims to know him, brought by the patient's emissary. Dead by the time Burma gets to the hospital, it turns out the patient was an anarchist fellow-traveller. The emissary is a young Gypsy woman and together they unravel the secretive old man's past. Campbell's dialogue in In a Pig's Eye has a realistic feel. It does not crackle, nor is it tough, as sewerage department worker and Democrat wardsman Flannery balances all the calls on his time. Here is a man who makes a success of neighbourhood-watch policing programmes, not by being excessively nosy, but by being a careful observer. When Mr P. Pig dies during his exercise class, Flannery notices a curious thing about the dead man's eyes. While The Song Dog is the latest Kramer and Zondi mystery, it returns to the start of their collaborative career. Both policemen are confident and cocky, which makes for some spirited interchanges, although they do not get together until well into the book. Kramer is sent deep into northern Zululand after a policeman and a white woman are blown up. His hard-headed approach carries the reader along as he encounters incompetence, reverence for the dead man and intransigence from some of his superiors.