Acronym for Known Associates. Usage example:

Bud parked three blocks over, walked up to the squadroom. No Exley, every desk occupied: men talking into phones, taking notes. A giant bulletin boar-d all Nite Owl--paper six inches thick. Two women at a table, a switchboard behind them, a sign by their feet: "R&I/DMV Requests." Bud went over, talked over phone noise. "I'm on the Cathcart check, and I want all you can get me, known associates, the works. This clown was popped twice for statch rape. I want full details on the complainants, plus current addresses. He had three pimping rousts, no convictions, and I want you to check all the local city and county vice squads to see if he's got a file. If he does, I want names on the girls he was running. If you get names, get DOBs and run them back through R&I, DMV, City/County Parole, the Woman's Jail. "Details". You got it?"

Via James Elroy, LA Confidential