He starts by solving a new crime in the 'serial killer case'.

You see, officially I'm not supposed to have anything to do with the serial killer cases yet.

I'm working on a serial killer case for Europol.

We have some information for you on the serial killer case.

He warned you these serial killer cases can take years.

We do, however, have a suspect in the transvestite killer case.

You worked a serial killer case in New Mexico about two years ago.

"That last serial killer case was only about two weeks ago."

"Could you really keep working on serial killer cases, and killing monsters, after you have a baby?"

McNulty continues sending men out for the serial killer case with little enthusiasm.