""I want this seared into your mind, son." - Harry, to teenage Dexter about Carl's death"
Carl is a character and serial killer in DEXTER. He was a man who killed eleven people and was sentenced to death for his crimes.
Not much is known about his early life except the fact that he is a serial killer who is responsible for the death of eleven people. At one point he was caught by Harry Morgan and was subsequently sentenced to death for his crimes.
He only ever appeared in a flashback where Harry takes Dexter to see him get executed. At his execution, many people were disturbed by the fact that a child was going to watch him die. After his death, however, Dexter learned the importance of not getting caught.