A Dorchester teen just weeks away from graduation was ordered held without bail today on charges he murdered a Forest Hills man who had arranged to sell him a pound of pot.

Charles Reddicks, 18, of Millett Street, was already out on $5,000 bail for a Dec. 11 drive-by shooting, in which he allegedly shot another teen in the arm at Columbus Avenue and Douglas Park from the passenger seat of a moving car to settle an earlier beef, the Suffolk County District Attorney's office reports.

Daniel Mulhern, chief of the DA's gang unit, said at Reddicks arraignment in West Roxbury District Court that Reddicks spent a good part of April 27 on his cell phone arranging a deal with Mariano Malave to buy a pound of marijuana.

Mulhern said the two agreed to meet at 132 Hyde Park Ave., where, in a hallway, Reddicks pumped several bullets into Malave. Malave was declared dead at the scene; Mulhern said video captured Reddicks driving away.

Reddicks had been a senior at Boston Latin School, but was expelled following the December incident, his lawyer, Rosemary Scapicchio, said. However, she said he enrolled in an alternative high school and got on the honor roll. She said he is hoping to take his finals in jail so he can get a high-school diploma rather than being forced to try for a GED later.

At his arraignment today, Reddicks stood behind a door, which meant about a dozen of Malave's family members and friends could not get a look at him. They sat in the second row of seats; Reddicks's mother sat alone in the first row.

Boston Police arrested Reddicks this morning near the Forest Hills rotary, not far from the murder scene.

Reddicks is next due in court on June 20.