Read again? Yes.
Number ten of 12!
Marlowe has just finished testifying in a Grand Jury on a murder. He's offered a job as a bodyguard by one Lou Harger, who has an angle on a roulette wheel he used to own. The wheel's at Canale's casino. Harger wants Marlowe along in case he starts winning and Canale gets pissy.
Marlowe takes the job and goes to the club as though he's just a customer, sitting at the bar and people-watching. Harger's girlfriend racks up more than $20,000 in winnings. But Canale has noticed Marlowe and asks him to leave.
He gets sapped before he even reaches his car. His gun is taken away...then the girl shows up at the office with the money and Harger turns up dead...and fingers are pointing at Marlowe as the killer.