Town House Dublin, €8.99

Five criminals – a rapist, a drug dealer, a wife killer and two child killers – have been murdered in Dublin in recent weeks. In each case the killer has been scrupulous in erasing his tracks, leaving only a business card from the 'messenger of the gods' – the Mercury Man, to link the murders.

The modus operandi for each killing is different and members of Dublin's Metropolitan Crime Squad are having a tough time establishing a lead – that is until a long shot put forward by Detective Garda Andy Fox yields some results. But Detective Inspector Donegan, has reason to believe that information on the victims is coming from an inside source. With all attempts to seek out this mole thwarted Donegan decides to go it alone and enlists the help of maverick detectives Fox and McGrath.

Author John Galvin is a serving Garda, and his second novel offers an unusual insight into the workings of the Garda Siochana, down to its hierarchy and poor opinion of journalists. 'The Mercury Man' is refreshing, thoroughly entertaining and not without its sparks of humour. Galvin looks to have a bright future in crime fiction.

Joanne Ahern