21 December 1988: Pan Am Flight 103 explodes in the sky over Lockerbie. Seventeen years on, Chris Petit analyses this infamous act of terror, describing it through the grief-stricken, suspicious perception of a man whose own life was saved by a chance, last-minute change of plan. But he had left his son to fly on. He goes to Scotland to join the ghastly search, not only for remains but also for an explanation.

Petit is a film director and novelist whose expertise in provoking powerful emotions makes his book more painful than would a less well-written treatment of this atrocity. Anyone who was personally affected by the tragedy should steer clear, for even as an outsider I found the vivid, immediate description of the disaster and its aftermath distressing, though horribly gripping. This mixture of fact and fiction, conspiracy theory and some real people – including, most vividly, the CIA spymaster James Angleton – is an adventure story but also a sophisticated, serious 'think piece' with multiple messages, all cynical, worldly and credible.

Sheila Quigley was a 57-year-old grandmother living on benefits in a council house when she got a six-figure deal for her first book, an up-to-date and true Cinderella story which seems incongruously fantastic beside this hyper-realistic police procedural, the third in a series though the first I have read. Its heroine is an overworked woman inspector described by previous reviewers as gritty and feisty. Her vocabulary seems pretty tame to me and she is ungrittily nice to the disturbed children and inept recidivists who populate her patch. The case begins with the apparent suicide of the only adolescent for miles around who was neither anorexic, obese or carving himself up with a knife, nor suffering from parental paedophilia, drug-use and drink. Take this authentic-seeming setting, throw in suspicious cults, a stroppy young woman constable and a gorgeous black sergeant whose boss fancies him , and the mixture makes a good read. But although no other word is printed as dialect, 'you' is always written as 'yer' – an affectation infuriating enough to be a book-spoiler.

Not so much death in Venice, more the disintegration of Venice, for the first corpse is not until page 126 and the crime is the threat to the city's survival with murder almost by the way. But the popularity of Donna Leon's long-running series does not depend on conventional detection. It is due to the intimate portraiture of place and people. Readers participate in the daily life of Commissario Brunetti and the Venetians whose parallel universe is shown as virtually unconnected to the Venice of the tourist hordes. This story begins with the political, at an environmental demo, and moves on to the personal, with death in a Murano glass factory. The murder seems to be connected with the victim's protests against the pollution of the lagoon and the damage to its unique, precarious ecosystem. A leisurely investigation is carried out over long lunches and quiet drinks, in boats and alleys, while winter gives way to spring and the foreigners return to join the uxorious Brunetti as he pauses on the way home for lunch, dinner and moral support, admires the sights of his beloved city and dreads its demise.

As often happens in this genre, synchronicity is at work: here is another death in a Murano glassworks and more revelations about the life that visitors never see. This cop is Roman, not Venetian, and wants to wrap his case up quickly and go back home. But the further he delves behind Venice's sparkling facade the more inscrutable the complications become. Hewson's very enjoyable Italian mysteries are cleverly worked out and sharply written, and his take on the secretive city is much more uncomfortable and sinister than Leon's. In his hero's eyes it is like 'a bad yet familiar relative, dangerous to know, difficult to let go'.

Another prize-winning poet turns to crime with Sophie Hannah's psychological cliffhanger. Alice insists that a changeling has been substituted for her two-week-old daughter. Nobody believes her until a police constable begins to rethink and takes another look at the ostensibly perfect set-up. Alice lives with her husband, his son, and his formidable mother. Though neither the situation or solution seem entirely convincing, the language and atmosphere are high quality stuff, and the portrait of a woman in the throes of post-natal depression will be a revelation to some, to others a reminder. The lonely, guilty, unmanageable emotions of a new mother are not always attributable to hormones and sleep deprivation. Sometimes they are grounded in reason.

McDermid's work can sometimes be too explicitly sadistic for me, so I opened this book nervously. In fact, it is safe for the squeamish and even one of her best. The story of academic rivalry in East London and murder in the Lake District is based on an intriguing notion: a tattooed body brought out of a bog was the Bounty mutineer Fletcher Christian, who had somehow made his way home from Pitcairn, gone into hiding with his cousin William Wordsworth, and inspired a long, but also long-lost poem. Historical information glides seamlessly into invention. I just wish a footnote had been added, to mark the join. Apparently Christian and Wordsworth really were related, but readers shouldn't need to do their own research to find that out.

More coincidence as another good writer builds her fiction on historical fact. When a professor is found dead his colleagues employ a private detective to second-guess the police. The notion of a wife and mother being given that job in 1896 takes some swallowing, but then the story goes down smoothly, seasoned with wit and intelligence and made out of unusual and interesting ingredients, including a careful discussion of anti-Semitism and 'the famous library paradox of Bertrand Russell'. There is even a brief appearance by the famous philosopher. The sedate university area of Bloomsbury is cleverly contrasted with an orthodox Jewish neighbourhood in East London and the factual icing on this clever concoction is a lucid account of one of history's most notoriously shocking miscarriages of justice, the Dreyfus case.

A happy seventh return to McCall Smith's Botswana and Mma Ramotswe of the Ladies' Detective Agency. The stories are only tangentially about detection, the crimes are petty and in each successive episode lessons on morals, manners and mutual respect are delivered with less and less disguise. Good people leading good lives do not often feature in this column, nor do detectives whose only equipment is insight and instinct, and moralising novels usually end up on my reject pile. But these books break all rules. They became worldwide bestsellers through word-of-mouth recommendation, not big-budget advertising; and they include details which would seem impermissible in other logic-based crime novels – for example, Precious Ramotswe 'senses' evil and acts on her belief without any of the evidence more conventional mysteries have to include. This combination of cautionary tale and comfort blanket, the ‘traditionally built’ (ie fat) detective and the portrayal of the 'old' Botswana are a delight.

Crime fiction is a broad definition, so Creed's thriller does come in the same category as McCall Smith's gentle tales, but they do share one quality: good, intelligent writing. Creed's action-packed adventure set in Northern Ireland follows an ex-spook, post-Bond loner who takes on the part of established officialdom that operates outside the law. The hero has to foil his own former colleagues, having discovered their dastardly plan to plant a plane crammed with chemical weapons in Iraq in order to prove the illicit WMD really existed. The commentary is acute and the narrative gripping but too often 'with one bound Jack was free', and I lost count of the corpses.