Special Guest Star Linda Blair (Detective Diana Ballard) is best known for her as the demon-possessed child Regan MacNeil in 1973's The Exorcist.

Unused scenes include:

1) Episode 507, Scene 22: Ballard and Sheridan talk about the circumstantial nature of the case. After sharing a brief kiss, Ballard asks if she'll have to cuff him and Sheridan says he hopes so.

1) Episode 507, Scene 30: Ballard talks to Sheridan in the hallway and asks if he's seen the words "Dana Shulpa" before. She's upset and Sheridan asks if she's all right, and Ballard insists that she's good.

Detective Diana Ballard: Thought you might be thirsty.
Sam: Okay, so you're the good cop. Where's the bad cop?
Detective Diana Ballard: Oh, he's with your brother.

Sam: I needed some time off. To deal. So, I'm taking a road trip with my brother.
Detective Diana Ballard: How's that going for you?
Sam: Great. I mean, we saw the second largest ball of twine in the continental U.S. Awesome.

Dean: What do you think, Scully, want to check it out?
Sam: I’m not Scully, you’re Scully.
Dean: No, I’m Mulder. You’re a red-headed woman.

Jeff Krause: I'm with the public defenders office. I'm your lawyer.
Dean: (deadpan) Oh, thank God. I'm saved.

Jeff Krause: Do you understand how serious these charges are?
Dean: I’m handcuffed to a table. Yeah, I get it. Humor me.

Dean: (on camera) My name is Dean Winchester. I'm an Aquarius, I enjoy sunsets, long walks on the beach, and frisky women.

Detective Diana Ballard: How did you get those? Those are from crime scenes and booking photos.
Sam: You have your job, I have mine.

Sam: You know, I think this is bothering me.
Detective Diana Ballard: Well, you are digging up a corpse.
Sam: No, not that. See, it's pretty par for the course, actually.

Dean: Pee break? So soon? You might wanna get your prostate checked.

Detective Peter Sheridan: We can pin the whole thing on him. No trial, nothing, just one more dead scum bag.
Dean: Hey!

Detective Diana Ballard: Unless... I just happened to turn my back, you walked away, I could tell them the suspects escaped.
Sam: Wait, are you sure?
Dean: Yes, she’s sure, Sam!

During Sam's first interrogation scene, as Ballard reads through Sam's file, he leans against the wall and folds his arms across his chest. When the shot returns to Sam, he crosses his arms again.

When Sam brings Dean coffee at the outdoor cafe, he starts to raise the cup to his mouth as he sits down. The camera cuts to a shot of him from the front, and the coffee cup is on the table.

When Ballard types up her report on the station computer, the form has "Occurrence" misspelled "Occurrance." It also lists Tony Giles' business address and phone as the same as his home address and phone, even though he was murdered at his office, and his business address is listed as the location of his death at the top of the form.

As Ballard and Sam leave Sam's hotel room, he puts his right arm in his coat sleeve. When the camera cuts to a shot from behind Sam, he's holding the coat in his right hand.

When Sam and Ballard find the lettering at the Ashland St. building, it is black letters on clear window glass. But when they look at the light shining through the window, the letters are indicated by the lights. This would mean the window would have to be blacked out and the letters were on clear window glass.

Episode Title: The Usual Suspects

The title of the episode shares the same title as the 1995 Christopher McQuarrie film about a man who tells a long, twisted story to police interrogators about a massacre and massive fire that took place in Los Angeles.

Dean: Does she look familiar to you?
Sam: No, why?
Dean: I don't know. Anyway, are you hungry?
Sam: No.
Dean: For some reason, I could really go for some pea soup.

Dean's comments break the proscenium, since they refer to the 1973 movie The Exorcist, a film that starred Linda Blair as the demon possessed child Regan MacNeil. Linda Blair played Detective Ballard in this episode, which perhaps not coincidentally features a threat that is not supernatural at all - the supernatural force here attempts to aid the victims of a very human killer.

Matlock

Dean and Sam, in separate conversations, refer to their public defender as "Matlock." Benjamin Matlock was a defense attorney portrayed by Andy Griffith on Matlock. Matlock was an expensive attorney, but since he always got his clients acquitted (usually in the grand Perry Mason style of proving who actually committed the crime) he was well worth the money. The form of address is certainly mockery, since many public defenders are green or incompetent (or sometimes both) - the antithesis of Matlock's experience and skill.

Scully and Mulder

Dean razzes Sam by calling him Scully. Scully and Mulder were a pair of FBI agents assigned to the "X-Files" division of the FBI. Like Sam and Dean, they investigated strange and outre happenings, although Scully usually provided a skeptical counterpoint to Mulder's willingness to believe. Sam and Dean are both aware that that creatures they hunt are very real. Scully and Mulder's adventures were recounted in the television series called, perhaps not surprisingly, The X-Files.

Dean: I'm not joking, Ponch.

In the 1970s series CHiPS, Erik Estrada's character, Officer Francis L. Poncherello, is nicknamed "Ponch".

Dean: You remember "redrum."

In The Shining, Danny writes word murder as "redrum".

Jim Rockford

Sam and Dean sign into the motel as Jim Rockford. Jim Rockford is the title character and Private Eye from the 1970s television series The Rockford Files.