Amid an ongoing special grand jury investigation, four Dorchester men and a Brockton resident were arraigned this week on murder charges stemming from the brutal stabbing of a 16-year-old last year. Police are still searching for a sixth suspect.

Those charged with murder included Markeese Mitchell, 16, of Brockton, with the rest from Dorchester: Admilson Vizcaino, 16; Terrance Pabon, 18; and Paul Goode, 25. Richard Allen, 20, is charged as an accessory.

Police say a sixth suspect, Pedro Ortiz, 28, of Dorchester, is on the loose but a bulletin remains out on him. "He'll turn up," B-3 police commander Capt. James Claiborne said.

The defendants, who were picked up on Feb. 29, pleaded not guilty in Dorchester District Court. District Court Judge Kenneth Desmond ordered that they be held without bail and ordered them to be back in court on April 3, according to Jake Wark, spokesman for Suffolk District Attorney Daniel Conley's office.

Claiborne said with the new detectives that were sworn in earlier this year, crime has stabilized. Detectives have more time to work on cases and are allowed "better quality of investigation," he said.

Car thefts and larcenies are down from last year, according to preliminary figures provided by police for January through March, but homicides, particularly in District C-11, robberies and aggravated assaults remain up. Homicides rose to 7 from 1 last year in the same time period in C-11, while B-3 saw 2 murders, up from 1, last year.

The May 22 murder of 16-year-old Terrance Jacobs, who was stabbed to death on Havelock Street by a group of six to seven teens, was one of 66 homicides last year.

"They're all known to police," said Claiborne of the suspects.

Prosecutors say the murder may have been the result of a fight with a group known to the Havelock and Wilcock streets group.

The incident occurred shortly before 8 p.m., with Jacobs sent to Boston Medical Center, where he died from multiple stab wounds.

According to Conley's office, the grand jury is continuing to take testimony, including some from over a dozen witnesses.