Two teens are called focus in quadruple-slaying probe

In the first sign of significant progress in the probe into who killed four young men in a Dorchester basement in December, authorities are set to launch a special grand jury investigation today focused on two Dorchester teenagers, two law enforcement officials with knowledge of the investigation said yesterday.

At least one of the teenagers knew the victims socially, the officials said, and the other has a lengthy arrest record. They have been the subject of significant police interest since soon after the Dec. 13 slayings on Bourneside Street, the officials said.

The officials said a major factor driving the decision to use an investigative grand jury is the power it gives prosecutors to compel reluctant witnesses to testify with the threat of possible contempt charges.

The crime, Boston's deadliest in a decade, stunned residents of the leafy, quiet Melville Park neighborhood and capped a year in which the city recorded 75 homicides, the most since 1995. At the time, Suffolk District Attorney Daniel F. Conley vowed that the crime would not go unpunished. Family members of the four victims, who met as students at Wakefield Memorial High School and shared a love for rap music, made emotional public pleas for justice.

Police have not issued an official statement on the investigation since Dec. 19, when they said they had searched a car belonging to one victim that was seen leaving the scene. Police have said that there was no sign of forced entry and that drugs, robbery, and gang-related activity were not probable motives.

Elaine Driscoll, a Police Department spokeswoman, and David Procopio, a spokesman for Conley, declined to comment yesterday on a grand jury investigation into the Bourneside killings.

''The overall investigation into the Bourneside homicides is active and ongoing," Procopio said.

Family members and friends of the slain men said they were pleased that authorities appear to be making progress in the investigation.

''My son was the only one who made it to the hospital; he was really holding on," said Linford Duncan, father of 21-year-old Edwin ''E.J." Duncan. ''E.J. would really want to see the person who did this sent to jail. He would like to see them get caught and punished for it."

A relative of another victim, Jihad Chankhour, 22, said his family will not rest until suspects have been arrested.

Family members of the other victims -- Christopher Vieira, 19, and Jason Bachiller, 21, declined to comment or could not be reached.

David Frank, a writer for Massachusetts Lawyers Weekly and a Suffolk County prosecutor in the gang unit until last year, said that prosecutors often use investigative grand juries to force witnesses to testify under oath.

''In a lot of cases, if a police officer approaches someone on the street, they don't have to talk to them," Frank said. ''If you hand a subpoena to someone and say, 'This is an order from the court, and you have to go to court,' it's a significant advantage for police and prosecutors. . . . The general principle is: If you get hit with a subpoena, you can't just ignore it. And if you ignore it, you can get arrested."

Frank said the purpose of investigative grand juries, which are ordinarily convened before a suspect's arrest, is often to strengthen the case by obtaining testimony under oath and by allowing prosecutors to run through the evidence before a jury.

''The general function behind an investigative grand jury is to basically call in anyone with a connection to a case and see where the evidence is going to lead," Frank said. ''In this day and age, with all the scientific evidence and all the cases being reversed on appeal, it's a smart move."

Frank said that in his experience, Suffolk prosecutors rarely convene investigative grand juries without a strong target for indictment.

Robert Griffin, a Boston criminal defense lawyer who once supervised grand jury cases as chief of Suffolk Superior Court prosecutions, said that investigative grand juries often lead to indictments.

In Massachusetts, all those charged with murder must be indicted by a grand jury before they can be placed on trial, though often that happens after a suspect is arrested and arraigned in the district court system.

Suffolk County prosecutors will conduct the special grand jury investigation into the Bourneside killings, but will use jurors impaneled by Attorney General Thomas F. Reilly's office, said the two law enforcement officials with knowledge of the probe.

The Suffolk County grand jury is among the state's busiest, and officials might be concerned that those jurors could be more distracted by other cases than the attorney general's panel, former prosecutors and defense lawyers said yesterday.

Also, the current Suffolk County grand jury will end in about three weeks, a law enforcement source familiar with the grand jury process said, and using the attorney general's grand jury will ensure that evidence is presented to a grand jury without interruption.

Griffin said Suffolk prosecutors are probably using the attorney general's grand jury because they believe it could lead to indictments more quickly.

''They may have a specific target in mind, and they may know that target is suspicious they're onto them," he said. ''There's a fear of flight, so they want to get the indictment [and] get a warrant."

Smalley can be reached at ssmalley@globe.com; Cramer at mcramer@globe.com. .