What does Baxter's information about the FBI having a suspect remind Harper of? Why?

Detective Baxter telling Harper about the suspect they have in their sights makes Harper uneasy. He is reminded of sitting in the New Orleans police station, saying that the killer's name is David Strobekker, and finding out minutes later that Strobekker was dead. He is afraid the same kind of thing will happen again, even though Baxter assures him the suspect is under surveillance.