A jury on Thursday acquitted one man accused in the execution-style slayings of three adults and a toddler on a Boston street and deadlocked on murder charges against another.

Edward Washington was cleared of all charges against him, including four charges of murder. Dwayne Moore was cleared of a drug charge, but the judge declared a mistrial after the jury deadlocked on the other charges against him, including murder.

After the verdicts were read against Washington, two women were removed out of the courtroom by officers after an outburst, and others followed them. Other onlookers buried their heads in their hands, or shook their heads and cried.

The verdict came after seven days of deliberations, following a monthlong trial for the September 2010 slayings, which prosecutors said happened during a drug robbery on a street in Boston's Mattapan neighborhood.

Washington and Moore were charged with killing 2-year-old Amani Smith, who was found in the arms of his mother, 21-year-old Eyanna Flonory. Also slain were Flonory's boyfriend, 21-year-old Simba Martin and 22-year-old Levaughn Washum-Garrison. The fifth victim, Marcus Hurd, survived the shooting.

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Defense lawyers challenged the credibility of the prosecution's key witness, Kimani Washington, who admitted taking part in the robbery, but said he left before the shootings.

Suffolk District Attorney Daniel Conley said he will retry Moore.

"We always believed firmly and strongly that Dwayne Moore was the executioner here," Conley told reporters outside the courtroom. "That's what the evidence was before this jury. They deliberated on it carefully. They weren't able to reach a verdict.

"But we expect that the next jury that sits on this evidence and hears it and understands it as we do will find defendant Dwayne Moore guilty for his terrible crimes."

Some relatives of the shooting victims, stunned by the verdict, left the courtroom and went to the nearby Statehouse, where they attempted to meet with Gov. Deval Patrick.

"The system failed us and we have no closure," said Mark Davis, an uncle of Eyanna Flonory. "The murderer just walked away who killed my niece and the baby."

Davis said relatives hoped to talk to the governor and express their concerns, but were told that Patrick was not available and that they could schedule a future appointment with him.

"Their anger was palpable and they wanted to see the governor to express their anger," said Mo Cowan, the governor's chief of staff. "They were concerned and confused about the verdict."

The jury reached decisions on 10 of the 19 counts Monday but was stuck on nine counts with one juror struggling over the "reasonable doubt" instruction. Judge Christine McEvoy sealed the partial verdicts and urged them to resume deliberating. Jurors on Wednesday came back to the judge to again say they has reached an impasse, but then made the unusual decision of voting unanimously to continue weighing the case on their own after McEvoy told them she could not force them to.

Both defendants faced four counts of first-degree murder, and single counts of aggravated assault and battery with a dangerous weapon, armed assault with intent to murder, armed home invasion, armed robbery, and unlawful possession of a firearm. Moore was also charged with cocaine trafficking.

The case hinged largely on the credibility of Kimani Washington, Edward Washington's cousin. Defense attorneys portrayed Kimani Washington as a thug, drunk, drug user, and pimp, who lied to investigators and was himself responsible for pulling the trigger in the shootings. Prosecutors acknowledged he is a career criminal but said other evidence backed up his version of events. He struck a deal with prosecutors for a 16- to 18-year sentence in exchange for his testimony.

Hurd, the survivor, testified he went to Martin's house the night of the shootings to buy marijuana and was shot after being ordered out of the house. He said he played dead and didn't see the shooter's face because the men wore hoods and he couldn't see their faces.

The early morning shootings sent tremors through the entire city, even though they occurred in a high-crime neighborhood.

Some of the victims were apparently dragged into the street naked before being shot.

The shooting was the single deadliest in Boston since December 2005, when four young men -- including three members of a rap group -- were fatally shot in a makeshift basement recording studio in the Dorchester neighborhood. Two men are serving prison sentences in connection with that shooting.

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