This Gotland-set series has really hit its stride; the sixth outing for Inspector Anders Knutas and his colleagues is a riveting read. The author begins by playing with a crime-fiction cliché harking back to Agatha Christie, when someone is killed by drinking cyanide at the opening ceremony of a conference centre on the island. More than 500 guests have gathered to celebrate this hopeful new chapter in the island's prosperity. The host of the party is event-planner Viktor Algard, who is handed the lethal cocktail by his new amour, as she needs to use the ladies' room.

Knutas and his wife Lina are at the party, but the inspector does not hear of the death until the next morning, when the cleaners discover a body in the lift. Hastily convening his team, Knutas quickly finds several possible motives. Of course, the reader knows before the police that the victim may not have been the intended recipient of the poison, and hence that all these motivations might be irrelevant.

In parallel with the police investigation, TV journalists Johan and Pia are working to cover Gotland news - Johan wants to dig into the story of a boy who was attacked two weeks ago outside one of Algard's clubs for teenagers, who has been in a coma ever since. Johan is shocked by the amount of underage drinking that goes on and the violence that results. He can't get his editor very interested in this issue until the murder, which could turn out to be connected.

The novel has two main strengths. The first is the way in which Knutas and his deputy, Karin Jacobssen, interview the witnesses and suspects, eliciting their stories. These vignettes provide vivid accounts of a range of personalities. The relationship of the two police officers as friends and colleagues is deepened. The second strength is the account of a man who, in occasional dedicated passages, is revealing the details of his unhappy childhood to an unknown listener. This particular device is over-used in modern crime fiction, but here the author avoids most of the pitfalls and presents a rounded picture of a person whose adult life has been blighted by his early experiences - the author really gets under the skin of the "narrator", and later on, provides some interesting comparisons between him and his siblings as adults.