Hooker At The Point
Craig Rasmussen (P.J. Brown) kills his mother-in-law. Then he goes to his wife's office and kills her and several of her co-workers.
This time, it's "Famous Guest Star Who Reluctantly Helps The Cops Catch The Perp": Patricia Arquette plays Jeannie, a prostitute who's had Craig as a regular for years.
"Tells me he has twenty bucks, he wants an around the world. He'll pay me later. I tell him, 'Honey, it doesn't work that way. Twenty bucks gets you a jack, and that's because we're friends."
The FBI agent assigned to the task force that's trying to apprehend Craig recommends letting Jeannie go back out hooking so that the authorities can use her as bait to catch Craig -- which is not a breach of procedure...unfortunately. It's just an unethical strategy that's depressingly common (see also: this New Yorker story about confidential informants).
Benson (Mariska Hargitay), who intervened in a fight between Jeannie and a john back in '92, when Benson was just a beat cop.
No verdict; using Jeannie as bait works, as she draws Craig out to a truck stop and gets into his latest stolen car, and remains there when a member of a SWAT team shoots Craig in the back of the head and splatters his brain all over Jeannie's face.
When Benson suggests that Jeannie go into rehab (for her drinking) and get out of the game, Jeannie gets to be the latest tertiary character to make Benson think about whether she's burned out: "You been doing your job as long as I have. What have you got to show for it?" Ring ring, hooker!