Donad E. Westlake: Somebody Owes Me Money (2008)
From the Publisher:
Chet knows he had nothing to do with it -- but just try explaining that to the cops, to the two rival criminal gangs who each think Chet's working for the other, and to the dead man's beautiful sister, who has flown in from Las Vegas to avenge her brother's murder...
Donad E. Westlake: Somebody Owes Me Money. Hard Case Crime, ISBN: 0843959622 (June, 2008), 256 p., $6.99