Who Is The Ice Truck Killer In Dexter?

"Dexter" may have featured a lot of memorable serial killers — including its protagonist –  but none of them attracted as much attention as the Ice Truck Killer. Absolutely committed to his villainy, Brian Moser (Christian Camargo) offs at least 20 people while using the identity of Rudy Cooper, before Dexter Morgan (Michael C. Hall) kills him during the first season. As with many of his other murders, Dexter slaughters the Ice Truck Killer in the same exact manner that Moser slayed his own victims — slitting his throat and tilting him upside down to allow his blood to drip free until he bleeds to death. 

Yet in an even more shocking twist, Brian turns out to be Dexter's biological brother. He, too, witnessed their mother meeting a grisly fate at the hands of Santos Jimenez (Tony Amendola). But Brian is not sheltered and taught the worth of justice by a Harry Morgan (James Remar) kind of figure. Instead, his impulse to follow his dark passenger and kill others isn't given any sense of moral or ethical boundaries. He kills because he enjoys it, because he thinks it's fun — and because he wants to lead Dexter back down the same dark road he's chosen. 

Brian's dreams of becoming a serial killing dream team with his little brother, however, are ultimately stymied forever. Dexter wants no part of who his older brother has become, even though he loves him. Because of Brian's heinous crimes, he sentences the man to death, stifling his own feelings on the matter. Naturally, though, nothing in the world of "Dexter" is ever simple.

Brian is an innocent kid, deeply attached to his little brother, when he and Dexter witness their mother's murder. Unlike Dexter, he is incarcerated in a mental hospital instead of being adopted. Harry finds and rejects him, noticing a darker streak in him than in Dexter. While hospitalized, Brian's desire to hurt others only festers, though he learns to behave like a normal, honest person. 

After aging out of juvenile detention, Brian drifts for a period as he takes up serial killing, swiping the identity of a man he murders, Rudy Cooper. All the while, he stalks his brother, getting closer and closer to him. He moves in on Dexter's adoptive sister Debra (Jennifer Carpenter) — whom he secretly loathes for taking Dexter away from him — eventually making her his fiancé. But all he wants is the old connection he had with his little brother, and he'll do anything to reestablish it. 

Brian goes too far in kidnapping Debra, hoping to talk his brother into killing her together and thus symbolically shedding his adoptive personality and identity. Instead, Dexter lures Brian into coming to his home, firmly rejects his idea of brotherly love, and kills him, leaving his blood-drained body to look like a suicide. It's one of the show's most jaw-dropping moments, even for Dexter himself, providing the series with one of its best episodes.

Dexter is the only mourner at Brian's funeral. He considers this such a loss that he doesn't take a souvenir slide of blood, as he typically does with all of his murder victims. But a younger version of Brian (Roby Attal and Xander Mateo) actually has a strong presence in "Dexter: Original Sin," a prequel series which examines his brother's earlier years.

During that show's run, Dexter is on his first case, investigating the "N.H.I. Killer," another alias pinned to Brian while he was in his early days as a murderer. While Dexter himself develops his moral code and keeps killing, Brian is on his own sad trajectory toward death and mayhem that's completely different from that of his bro.

It's Harry who begins to realize that Brian is the serial killer they've been hunting. Unfortunately, that means facing the boy he rejected, leading to an untimely confrontation. While Harry can't rescue Brian from his fate — nor Dexter from his — he does try. But the brothers are destined to be rivals, in both slaying and in life. It's only Debra who proves to be Dexter's ultimate breaking point — and his reason for clinging to his humanity in spite of it all.