Here is the official description for Chicago PD season 2 episode 20, "The Number Of Rats" - airing April 29th.
Continuation of Chicago Fire, "We Called Her Jelly Bean" episode...
SVU DETECTIVES JOIN CHICAGO INTELLIGENCE TO CONNECT A CASE IN CHICAGO TO AN UNSOLVED CASE ABOUT RAPE AND MURDER FROM NEW YORK A DECADE PRIOR
Benson has traveled into Chicago to help Voight and intelligence with a rape/murder case that is frighteningly similar to a case from New York a decade ago. She calls in Fin and Amaro to assist. The prime suspect, Yates is let go after rigorous questioning. He then requests a meeting with Lindsay and he warns of unintended consequences from what intelligence is doing.
Benson (Mariska Hargitay)
Voight (Jason Beghe)
Amaro (Danny Pino)
Yates (Dallas Roberts)
Lindsay (Sophia Bush)
guest & recurring cast:
Jesse Lee Soffer