Hello and welcome to best case, worst case.

My name is Maureen O'Connell and I'm your co-host today and I am a 25-year veteran with the FBI

and I was on the FBI ZRT team for 20 years.

And with me today is my handsome co-host. Wait, wait, wait, I'm here today,

not your handsome co-host. I know. I know. I just noticed that.

City prosecutor and writer-producer of criminal minds. And today we have two very special guests.

Good afternoon. My name is Will Sveilar. I am a retired Chicago police officer. I was a homicide detective, retired as a rank of commander in the detective division. Like I said, 32 years experience. And we got another top-notch homicide guy with us as well.

Hi. My name is Tim Murphy. I'm a 35-year veteran of law enforcement.

I work for a Chicago Police Department as a homicide detective for over 22 years and was a cold case homicide detective.

And then finished up my last seven years as a detective working officer involved shootings and officer involved fatalities.

Well, thank you for coming, both of you, Will and Tim.

So today, I'm best case, worst case.

We'd like to talk to you about a case that's either a best case or a worst case for you.

And I understand there's a case that you two work together.

Where were you in your careers when this case came in?

This was early November of 2015. I was a day shift homicide supervisor in Area 2, which is on the

far south side of the city of Chicago.

And Tim?

I was working cold case out of that office area two detective division with my partner, Danny Stover.

And how did you guys find out about this case?

I was sitting in the office when the call came in of a person shot in a park

in the 6th District. Like all homicides, I rolled out there with a team and there was an afternoon

...