After three trials in as many years, the leader of a deadly Boston street gang and his gun-toting triggerman were convicted of all indicted charges for the 2007 murder of 18-year-old Cedirick Steele, Suffolk County District Attorney Daniel F. Conley said today.

A Suffolk Superior Court jury today found ANTWAN “TWIZZ” CARTER (D.O.B. 10/13/88) and DANIEL “TRAP” PINCKNEY, Jr. (D.O.B. 7/4/88), both of Boston’s South End, guilty of first-degree murder and unlawful possession of a firearm for the Bunker Hill Community College standout’s shooting death near the Timilty Middle School. The verdict followed about two weeks of testimony and a day and a half of deliberations in these proceedings.

The pair’s most recent trial followed two mistrials, both declared after previous juries were unable to reach unanimous verdicts. They have remained in custody since their October 2007 arrests by Boston Police after a seven-month investigation on the street and in the Suffolk County Special Grand Jury.

“People asked us why we would try this case a third time,” Conley said. “The answer is that we would have tried this case as many times as necessary. We will not stop. We will not relent. We will not rest until justice has been done. Was it worth it? Yes. At long last, we were able to speak loud and clear on behalf of an innocent young man whose only crime was to stand across the street from a middle school in the City of Boston. At long last, we were able to speak for the family from whom he was stolen. And at long last, two deadly gang members are off the streets for good.”

Members of Steele’s family were overcome with emotion as the verdict was read and after the jury filed solemnly out of the courtroom.

“No one else knows what we’ve been through but you,” the slain man’s cousin sobbed to a paralegal who worked on the case.

In the most recent trial, First Assistant District Attorney Josh Wall proved that Pinckney and Carter were members of the Mass. Ave. Hornets street gang angry about a previous shooting that injured one of their associates. On the afternoon of March 14, 2007, the evidence showed, they drove in Pinckney’s black Pontiac to a Roxbury park to retaliate against someone from the Highland Street area, whom they believed to be responsible. When they saw those rivals on Dorr Street, however, they were afraid of being shot at.

The evidence showed that the pair drove to Carter’s home, where Carter retrieved a 9mm semiautomatic handgun. They then picked up Pinckney’s girlfriend, whom prosecutors say was expected to take the gun after the shooting and remove it from the car in case they were stopped.

At about 4:00, the trio pulled into an alleyway in the area of John Eliot Square. Pinckney instructed Carter to take the girl’s gloves and get the gun ready.

“Hit anyone,” Pinckney said.

Carter did just that, the evidence showed. The young man he killed near the corner of Highland and Centre streets was not a gang member. He was a promising student who delivered meals to the elderly and stayed away from guns and violence.

Carter shot him eight times in the chest, killing him. He then ran to Pinckney’s car. Pinckney drove him from the scene. When Carter tried to give Pinckney’s girlfriend the gun, she refused to take it. She later left the vehicle and went to her mother’s nearby home.

Jurors in all three trials heard calls and read letters in which Carter tried to have her silenced or killed after she bagn speaking with the Boston Police homicide detectives who had been investigating Steele’s death since it took place. Despite those efforts, the young woman testified in each proceeding.

Conley hailed those detectives and the trial team of prosecutors, victim advocates, paralegals, and civilian investigators who put hundreds of hours into the case.

“Each and every one gave this case one hundred percent,” Conley said. “Today, those efforts paid off.”

Carter was represented by attorney Barry Wilson and Pinckney by James Greenberg. Kara Hayes was the DA’s assigned victim-witness advocate. Judge Linda Giles will sentence both men to the mandatory life term without the possibility of parole tomorrow at 9:00 a.m. in courtroom 806 of the Suffolk County Courthouse.