Suffolk County District Attorney Daniel F. Conley and Boston Police Commissioner Edward Davis today announced the arrest of a notorious gang leader for the murder of one young man and the shooting of another amid a week of violence three summers ago that left five dead and six injured by gunshots.

JAMES A. WALKER, a.k.a. “GUNNA” (D.O.B. 9/9/86), of Dorchester was arrested today for the fatal shooting of 20-year-old Antoine Perkins and the non-fatal shooting of a second man, then 19, in Dorchester on the night of July 22, 2006. Walker’s arrest, effected by Boston Police homicide detectives, comes in the course of an extensive investigation by Suffolk prosecutors in the Suffolk County Grand Jury.

“Our determination to see justice done doesn’t diminish with the passage of time,” Conley said. “Antoine Perkins’ family has waited for the day that his killer would be held to account, and this arrest – like the interagency partnerships that preceded it – brings us one step closer to that result.”

Davis stated, “This was a long term investigation and one where we delivered on our promise to use every lever available to us to take violent offenders off our streets. In this instance, we were able to utilize drug laws while investigators and prosecutors built a strong murder case. I would like to commend the investigators who worked tirelessly to secure justice for the Perkins’ family. I would also like to thank Federal and State prosecutors who worked with us to remove this dangerous individual from our community.”

At the time of his arrest, Walker was in federal custody in connection with his 2007 arrest on drug charges brought during a crackdown on the Lucerne Street Doggz street gang, of which he is believed to have been a leader.

Walker allegedly fired on both victims shortly before 11:45 p.m. on Morton Street, striking Perkins in the head and causing injuries that claimed the young man’s life at the Boston Medical Center two days later. The surviving victim was struck in the ear, causing injuries that were not life-threatening. Police and prosecutors believe all three were known to one another.

Walker was one of 25 members of the Lucerne Street Doggz prosecuted in state and federal courts on gun- and drug-related offenses following a joint investigation by Boston Police; Suffolk prosecutors; the United States Attorney’s Office; the Bureau of Alcohol, Tobacco, Firearms, and Explosives; and the Drug Enforcement Administration.

Walker is expected to be arraigned tomorrow morning in Dorchester District Court.