Dean's ringtone is "Smoke On The Water" by Deep Purple.

The photo of one of Holmes' victims that Sam examines is actually of Elizabeth Stride, one of Jack the Ripper's victims.

Dean: Young girl's been kidnapped by an evil cult.
Sam: Yeah. The girl got a name?
Dean: Katie Holmes.
Sam: That's funny. And for you, so bitchy.

Dean: We rarely drink before 10, anyway.

Jo Harvelle: Three weeks ago, young girl disappears from a Philadelphia apartment. (hands Dean the file) Take it, it won't bite.
Dean: No, but your mom might.

Dean: You know, you shouldn't lie to your mom. You shouldn't be here, either.
Jo Harvelle: Well, I am, so untwist your boxers and deal with it.

Sam: Where’d you get all that money from, anyways?
Jo Harvelle: Working at the Roadhouse.
Dean: Hunters don’t tip that well.
Jo Harvelle: Well, they aren't that good at poker, either.

Jo Harvelle: So, you gonna buy me dinner?
Dean: What are you talking about?
Jo Harvelle: It’s just if you’re gonna ride me this close, it’s only decent you buy me dinner.
Dean: Oh, that’s hilarious.

Dean: My dad started me in this when I was so young, I wish I could do something else.
Jo Harvelle: You love the job.
Dean: Yeah, but I'm a little twisted.
Jo Harvelle: You don't think I'm a little twisted, too?

Jo Harvelle: (on the phone) Thanks, Ash, and if you breathe a word of this to Mom… that’s right. I will. With pliers.

Dean: (on the phone) Yeah.
Ellen Harvelle: You lied to me. She's there.
Dean: Ellen.
Ellen Harvelle: No, Ash told me everything. The man's a genius, but he folds like a cheap suit. Now you put my damn daughter on the phone.
Dean: She's gonna have to call you back, she taking care of... feminine business.
Ellen Harvelle: Yeah, right. Where is she? Where is she?!?
Dean: Look, we'll get her back.
Ellen Harvelle: Get her back? Back from what?
Dean: The spirit we're hunting, it took her.
Ellen Harvelle: Oh my God.
Dean: She'll be okay, I promise.
Ellen Harvelle: You promise. That is not the first time I've heard that from a Winchester.

Sam: So, this job as glamorous as you thought it would be?
Jo Harvelle: Except for all the pee-your-pants scares, yeah, sure.

Jo Harvelle: You ripped off a cement truck?
Dean: I'll give it back.

Dean: Well, you really weren't kiddin' about flying out, were ya? (Ellen remains silent) How about we listen to some music? (Foreigner's "Cold As Ice" blares out the radio and Ellen switches it off) This is gonna be a long drive.

Jo states that Moyamensing Prison was built in 1835 and demolished in 1963. However, Moyamensing Prison was actually torn down in 1968.

In reality, H. H. Holmes had blue eyes, not brown eyes as seen in this episode. In addition, Sam states that Holmes was buried in several tons of concrete. He was actually buried in an unmarked grave in Holy Cross Cemetery.

When Dean prepares to enter Holmes' underground chamber, he hands the gun to Sam and is holding it by the barrel. However, when the camera cuts instantly to the next shot, he's holding it by the butt.

Sam: Yeah, and does this girl have a name?
Dean: Katie Holmes.

Katie Holmes is a reference to the actress of the same name known for her role as Joey on Dawson's Creek as well as her relationship with Tom Cruise.

Dean: It's the Stay Puft Marshmellow Man.

The Stay Puft Marshmellow Man is a reference to the 1984 Ghostbusters film where a battle with a marshmellow man takes place near the end of the movie.