WASHINGTON, DC (WUSA) -- DC Mayor Adrian Fenty calls it "one of the most violent crimes that has ever happened in the city."
Now, his police department is admitting a major mistake in its investigation of a March 30 drive-by shooting on South Capitol Street in which four persons were killed and five others were injured.
Following a high-speed chase on the night of the shooting, occupants of the van from which the shots were fired left the vehicle and ran away, followed by police on foot.
Police made several arrests, among them a 14-year-old boy they accused of being the driver of the car from which the shots were fired. One officer filed documents saying she identified the boy as the driver of the van.
Now, police say they were wrong and that the boy had nothing to do with the crime.
Police blame the chaos of the chase and reluctance of witnesses to help in the investigation.
"In an ideal world all of the witnesses would have come forward and given us statements that night. They didn't," said Police Chief Cathy Lanier.
Two additional arrests were made in the case Thursday, bringing the total of those in custody to four.
Charged Thursday were 22-year-old Robert Bost and 22-year-old Lamar Williams. Already in custody after earlier arrests are suspects Orlando Carter and Nathaniel Simms.
An additional person has been charged, but is not yet in custody.
"I am not going to release the name of that individual out of fear for that person's safety, but I am urging that person, or those who know that person, to have him come forward for his own safety, and turn himself in, because we will find him and we are actively looking for him, and he owes it to the family members of the people involved in this case to come forward," Lanier said.
Police say they made a public display of dropping the charges against the 14-year-old so that he would not be targeted for retribution. They want it made clear he had nothing to do with the crime, and was not a witness to it.