When Cole is at the cematary he continues to morph back and forth between his human/demonic half. Each time he does, his suit is different (all black as Belthezor and navy blue jacket/white dress shirt as Cole). However, when at Cole's apartment, once Phoebe leaves to get Leo, Cole begins to do it again, only this time his shirt stays the same while morphing back and forth. A shirt by the way, that was different than both shirts worn by his human and demonic halves at the cematary!
At the cemetary when a weakened Cole is morphing back and forth between his human and demon self, his suit keeps changing. Since Cole/Belthezor is still only one person, wouldn't he only get dressed once?
In this episode, Leo encourages the girls to work with Krell. However, in the season two episode, Apocolypse Not, Leo, even before learning that they were the Horsemen, was adamant that they should never work with evil!
TRIVIA: Cole is not the first evil being to fall in love with a witch/mortal while on the job. Prior to Cole the Charmed Ones had battled Anton the warlock, Drasi, Alec the darklighter and the Necromancer, all of whom fell in love with good woman while initially using them for something else! Cole, however is the only one to ever attempt to turn good as a result.
Why did Leo have to take off Cole's bandage to heal him? He never had to before.
The reason Piper froze the bounty hunter demon was because she didn't want to have to repair the clock again. But when she unfreezes the demon he crashes into the clock and Piper says, "It was worth it". Why couldn't Prue have moved the clock instead?
TRIVIA: This episode reunites Holly Marie Combs with Keith Diamond, they last worked together in the 1992 film "Dr. Giggles". In the horror movie, Holly played the part of Jennifer Campbell and Keith Diamond played Officer Rietz.
At the end when Phoebe reassured Prue that she was right about Cole, Prue said, "I didn't want to be right." Paige said the same thing in season 4, when Phoebe found out that Cole was the Source.
When Prue launches Krell across the room, Piper freezes him before he crashes into the clock. In his frozen state his legs are suspended in the air and his arms above his head. In the next shot when Prue and Piper approach his frozen body his legs are down vertical to his body and his arms are off to the side instead of in the air.
TRIVIA: Phoebe discovers that Cole is a demon in this episode.
When Cole is trying to leave the cemetery, he asks the woman at the funeral if he can bum a ride, and she asks him if he is going to the wake. Wakes are held before funerals, it is when the body is usually shown at the funeral home.
Cole: Wait. I won't hurt you.
Phoebe: No? It's a little too late for that, don't you think?
Prue: All right, listen, here's the deal. Belthazor killed the Triad, now The Source wants him dead. Krell is trying to suck up to The Source, so he wants to kill Belthazor.
Piper: Belthazor wants to kill us so The Source won't kill him.
Leo: And if you work with Krell, you can vanquish Belthazor before he kills you.
Phoebe: Works for me.
Piper: I don't understand. How can you not know that the Triad is dead? Don't you think that's kind of important? Especially since, I don't know, they've been trying to kill us for the past two years?
Leo: We've heard rumours, talk, but that's it. Nothing substantiated.
Piper: Well, I guess you can substantiate it now, can't you?
Phoebe: It just doesn't help that you never liked Cole from the beginning.
Prue: Yeah, well... I mean, you never really liked any of my boyfriends either.
Phoebe: That's very true.
Prue: We're gonna vanquish him.
Piper: We're gonna vanquish Phoebe's boyfriend? That's going to cause some problems.
(Prue puts one of the pig's feet into the potion)
Piper: Poor piggy.
Phoebe: How can we forget the Belthazar flesh?
Prue: Such a slacker.
Piper: Give me a second, lady...
Prue (about Krell): Alright, that doesn't make sense. How did we get the wrong demon? Hey, do you think that you could just unfreeze his head? That way we could ask.
Piper: His head?
Prue: Yeah his head.
Piper: Why not? (she unfreezes his head only) That's different.
Prue: That's cool.
Piper (after throwing a potion): There's no boom. Why is there no boom?
Prue: I don't know.
Krell: What did you do to me?
Prue: Uh, hi, you know what? You're sort of frozen in mid-air, therefore, we'll be asking the questions, okay? Who are you?
Krell: Someone who's gonna butcher you if you don't unfreeze me right now.
Piper: Okay. (She unfreezes him, and he slams into the grandfather clock. Prue scowls at her.) What? It was worth it.
(Prue kicks him as he lies on the ground.)
Prue: Alright, you start talking or we start the bonus round.
Krell: I am Krell, a Zotar.
Prue: Hi, I'm Prue, a Scorpio.
Piper: Attack of the killer pig's feet.
Prue: Pig's feet.
Prue: So you can slice off a chunk of demon flesh, but you can't touch a pig's foot?
Piper: I'm a vegetarian.
Prue: Since when?
Piper: Since now.
Krell: Just the thought of working with you two turns my stomachs.
International Episode Titles: Czech Republic: Stopování s nepřítelem (Trailing with the Enemy) France: Démon contre démon (Demon versus demon) Italy: La confessione (The confession) Germany: Balthazar (Belthazor)
This episode scored 5.7 million viewers.
Piper: Attack of the killer pig's feet.
An allusion to the late 1970's to 1980's film series Attack of the Killer Tomatoes.
Title: Sleuthing With the Enemy
This is a reference to the saying "sleeping with the enemy" and also a reference to the 1991 film Sleeping with the Enemy, starring Julia Roberts.