Exit Music (Inspector Rebus #17) by Ian Rankin

It's late autumn in Edinburgh and late autumn in the career of Detective Inspector John Rebus. As he tries to tie up some loose ends before retirement, a murder case intrudes. A dissident Russian poet has been found dead in what looks like a mugging gone wrong. By apparent coincidence, a high-level delegation of Russian businessmen is in town - and everyone is determined that the case should be closed quickly and clinically.