Luis Pimentel, 18, is charged with shooting Victor Brookens to death in a fight over marijuana the teen thought the 54-year-old man was hiding in his Samoset Street apartment, the Suffolk County District Attorney's office said today.

Pimentel, arrested by Boston Police detectives this morning at 20 Wales St. in Dorchester, was ordered held without bail at his arraignment today for Brookens's Dec. 10 murder. According to a statement by the DA's office:

"Assistant District Attorney Ursula Knight said Pimentel had planned to rob Brookens, believing that he would find marijuana and cash at his residence. Armed with a handgun, Pimental allegedly shot Brookens during the course of that robbery.

"Knight told the court that Pimental made statements indicating that he had brought the gun for protection and acted in self-defense when Brookens pulled a knife."