I Know What Scares You - S4.E18

Tina and Alexa, two college roommates, go to the police station after continuously receiving harassing phone calls. Chris tells them that he is from Homicide and cannot help them. The next day, Tina shows up dead in her car, and Alexa says it is all Chris' fault. Later that night, while Alexa and her boyfriend Jeff are in bed together, Jeff whispers to Alexa, "I know what scares you"--the same thing the killer used to say to Tina. Alexa locks herself in the bathroom, and once Jeff leaves, she goes to the police station and tells them what happened. So Chris and the Captain decide to investigate Jeff Chadwick's past. Meanwhile Rita is busy with the Costanzo Case; and Chris tries to smooth things out between his friends Rick and Liz Faraday--who are arguing over the same salary issues Chris and Jillian argued about.