On the calendar at the Park County Police Station, there were only 6 days in a week.
Kyle first argued with the FBI that the boys have been working on the stolen doll case since 2:30.
Later in Fossy's house, the grandfather clock would show the time of 1:59.
The first dollar that the boys earned was coded 'G04078844A'. However, in the next scene, it was changed to 'J23669620Q'.
The latter note also appears to have fold lines, with different signatures on both sides and sequential numbers.
Cartman's sign language to Kyle:
I - One finger up and out
See - Two fingers pointing to the eyes
Two guys - Two fingers turned out
Inside - Thumb pointing the house
They have - The grabbing gesture
Sarah - fist
Peterson's - thumb up
Doll, - fist, turned out
You - pointing to kyle
Stupid - finger to the temple
Jew! - "J" sign on the hat
On the part where Butters gives a semen sample he's in the bathroom for a while and at the end he said he was in the bathroom for two days straight. However, between the part where he goes in the bathroom and when he gets out there's a school scene and Butters is in the classroom.
Kenny's blond hair is visible in the locker room because he took off his hood. This is one of the only episodes where we see any of Kenny's hair.
Who sent the boys the hot tip, which leads to finding the doll? The only two who knew where the doll was were Bill and Fosse, but they were surprised when the boys showed up.
When Cartman is signaling Kyle, Cartman is at the front door and Kyle is at the corner of the house. A moment later, when Stan and Kenny run towards the door from the lawn, Kyle is with them. Wouldn't Kyle have run along the side of the house to get to the door, not towards the house?
In the episode "Jared Has Aides," Cartman says to Butter's dad, "I'm just jacking it... my hot spicy boner, of course." Yet in this episode, it's ironic that he doesn't know how to get a semen sample or about (as Kyle or Stan puts it) 'masterjuvating' it.
Funny, Kenny steals Playboys from his dad but doesn't know how to get a semen sample.
Near the episode's beginning, Stan proudly displays the boys' first dollar earned. But in the very next shot, the bill displayed is completely different (different serial number, treasurer signature, bill condition, etc.)
When the boys are getting changed to go into the shower Cartman takes off his hat, but in the next scene Cartman has his hat back on.
Stan: Bang, bang, bang. I got you, Fossy!
Fossy: No you didn't!
Stan: Did so!
Fossy: No, cos I got special wizard armour on.
Kyle: We're not playing Dungeons and Dragons, xxxface!
Cartman: Well, if they won't give us the doll, then we have no choice. Let's go tell on them.
Fosse: Detectives, if you don't get out of here, we're gonna rip the doll's head off!
Fosse: We were playing gynecologists and now we're playing criminals.
Bill: That's gay.
Fosse: We're gay.
Old Woman: Two days ago I put a fresh baked cherry pie out on my window sill to cool. And later, when I went to get it, it was gone.
Cartman: My God.
Butters: Fellas! Hey fellas! I got it! Ah, I got my semen sample!
Cartman: You did?
Butters: Yeah. I was up there poundin' my wiener for two days straight, and finally, I thought about Stan's mom's boobs, and this little tiny spooge of this white stuff came out!
Liane: Eric, where have you been? It's 10:30.
Cartman: We had to take down a meth lab on Mala Vista.
Liane: Well, you should've called Mommy.
Cartman: Will you get off my back? It's hard enough I got to work the beat, and now I got to come home to your nagging? [realizes what he's doing] Look, look, I'm, I'm sorry. It's just this case, and the guys down at the station, I, I'm tired, alright? I'm, I'm tired.
(the boys examine Sarah Peterson's room)
Cartman: No sign of forced entry.
Kyle: But the window isn't locked.
Stan: Right, so it's possible that the thief sat out in that tree. He would have watched Sarah with the doll, possibly while cutting the palms of his hands with a large knife. The pain gave him sick pleasure.
Kyle: Disposing of the doll wouldn't be easy. He would have had to have brought a shovel to decapitate it.
Cartman: We're going to need semen samples from everything in this room.
Fosse: They're playing Detective.
Bill: That's gay. [they giggle]
Stan: Just because your parents can afford better toys than ours doesn't make you better than us!
FBI Kid: Yes it does so!
Lt. Dawson: …I'm hereby making you all junior detectives. That means you boys are now an official part of the department. Alright, so ready for your first assignment? Okay, there's a meth lab down at 567 Mala Vista. The operators are probably armed to the hilt with illegal weapons: I want you to get down there and see what you can find.
Stan: Uh, a meth lab?
Lt. Dawson: I don't want any problems, just take them down by the book. Now get over there, the mayor's on my ass about this one. Oh, and deputies, you screw this one up, and I'll have you working graveyard shift behind a desk.
Kenny: (muffled) Patoo! Patoo!
Cartman: Kenny, it doesn't go "Patoo! Patoo!", it goes "Bang bang bang!"
Butters: Ah, I'm pullin' on my weiner, but nothin's happening.
Cartman: Well pull harder!
Butters: Ow, ow... It's not workin'.
Cartman: Try doin' it faster.
Butters: Ow ow ow ow ow ow ow ow ow ow ow. Naw, nothin'!
Mr. Garrison: Uh, boys! Would it trouble you terribly not to sleep in my class?
Kyle: Uh, we weren't sleeping, Mr. Garrison.
Mr. Garrison: Oh well, then maybe you can tell me who was in charge of the feminist movement of the early sixties!
Cartman: A bunch of fat old skanks on their periods?
Mr. Garrison: Right, but who was the fattest oldest skank on her period?
Lt. Dawson: I don't know how they do things down at that dog-and-pony show they call the Fourth Grade, but here we have rules!
Cartman: Guys, did you hear that? Butters doesn't know how you make semen come out of your body.
Kyle: How do you make semen come out?
Cartman: I don't know. I was hoping you guys did.
(the theory of who took the pie)
Stan: You said you set the pie in the window sill, where it must have sat for some time. But it's sweet smell attracted the attention of somebody.
Kyle: Your husband. He wanted that pie badly, but he knew that he was not allowed to eat it yet.
Cartman: Slowly the rage built inside his mind. "Why won't she let me eat that pie? Why does she always stop me from doing what I wanna do?" His only solution became obvious. Kill her!
Stan: His plan was to use a hammer.
Cartman: Bash, bash, bash your skull in, causing instant death.
Stan: Then to make it impossible for police to identify the body, he'd use a shovel to remove your head.
Kyle: Then saw off the arms and legs.
Cartman: The torso he would dump into the lake.
Stan: The arms and legs he would dissolve with acid and lye in the bathtub.
Cartman: And then, finally, he'd be able to eat that pie.
Kyle: But before he could go through with this entire plan, he discovered that the pie had already been eaten by your dog.
This is Isaac Hayes's 100th appearance as Chef.
Stan's hair resembles that of Trey Parker's who happens to be the voice of Stan. This is also the case with Kyle's hair resembling Matt Stone's, who is also the voice of Kyle.
The voice of the head kid FBI agent is the same as the voice of Josh in "Toilet Paper".
The Peppermint Hippo strip club is a parody of the Spearmint Rhino Gentemen's Clubs.
This entire episode was referencing the TV series CSI.
The part where the boys come up with a theory for how the pie was stolen (which involved the old lady's husband killing his wife and doing gruesome things with it), was a reference to some of CSI's absurdity. Even the color of the screen was similar.