Two men were arraigned today for their respective roles in February and July murders about a block away from one another, Suffolk County District Attorney Daniel F. Conley said.

Suffolk prosecutors recommended that the alleged killers of 38-year-old Thomas Speed on Feb. 11 and 21-year-old David Brimley on July 4 be held without bail during proceedings in Roxbury District Court today. GARRETT JACKSON (D.O.B. 7/13/87) allegedly shot Speed to death at 18 Trotter Court, while CHARLES WILLIAMS (D.O.B. 8/24/79) allegedly shot Brimley to death around the corner at 617 Shawmut Ave.

Boston Police took both men into custody late yesterday after Suffolk prosecutors approved separate warrants for their arrests.

Roxbury District Court Judge Edward Redd set Jackson’s bail at $250,000 cash, further ordering him to wear an ankle bracelet if he posts that amount. Redd ordered Williams held without bail.

Assistant District Attorney Gretchen Lundgren told Redd that Speed and Jackson were well known to one another and that “the murder of Tommy Speed was nothing short of a planned execution.”

Shortly after 8:00 on the night of his murder, Lundgren said, Speed was approaching 18 Trotter Ct. At the same time, the prosecutor said, Jackson was “waiting calmly” outside the same address. As Speed walked in, Jackson allegedly fell in step behind him and shot him in the head at almost point blank range.

Jackson allegedly fled the scene on foot. Emergency medical technicians responded and pronounced him dead at the scene.

During Williams’ arraignment, Assistant District Attorney Jennifer Hickman told Redd that Brimley walked to the scene of his death after receiving a series of phone calls shortly after 2:00 p.m. He then engaged in a conversation with a man described as “basketball tall.”

After a few minutes, the tall man pulled a semiautomatic handgun and fired multiple shots at Brimley, who was struck three times in the abdomen and once in the wrist.

During the investigation that followed, the tall man was identified as Williams, who stands 6”8” tall and has a lengthy record including gun and armed robbery convictions.

Jackson is represented by attorney Barry Wilson and will return to court on Aug. 12. Williams is represented by attorney James Greenberg and will return to court on Aug. 14.