The Cutie — Donald E. Westlake

SOME PEOPLE WILL DO ANYTHING FOR MONEY
Mavis St. Paul had been a rich man's mistress. Now she was a corpse. And every cop in New York City was hunting for the two-bit punk accused of putting a knife in her.

But the punk was innocent. He'd been set up to take the fall by some cutie who was too clever by half. My job? Find that cutie â€" before the cutie found me.