The Tailor by Tim Sullivan

In the eighth book of the DS Cross series, George's team is investigating the death of tailor Billy Titcomb, who was brutally murdered in a train lavatory. What could Billy have been involved in that would cause someone to kill him so violently? As George looks into Billy's business and personal life, he wonders if Billy's wife Min, a chemist who was born in China, could be involved. Another satisfying entry in the series.