The man charged with killing 15-year-old Myesha Lowe last month in Northeast Washington has been linked by a witness and by physical evidence to a killing 10 days earlier, according to court documents and testimony.

Joshua Ross, 20, who was in D.C. Superior Court yesterday for a hearing, is charged with first-degree murder in Myesha's July 24 slaying.

A promising student, Myesha was due to leave on a group trip to Niagara Falls the next day. She was shot and mortally wounded as she and two friends sat in a parked car in the 1400 block of F Street NE.

Court documents show that Ross was identified by a witness as one of three participants in a deadly armed robbery July 14 in the 1200 block of Holbrook Terrace NE.

Gregory Givens, 19, of Richmond was killed, and two people, ages 18 and 21, were wounded in the robbery, which took place about 11:30 p.m. in the Trinidad neighborhood.

Like Myesha's killing, the robbery on July 14 involved three assailants, and investigators have determined that the same two handguns -- a .40-caliber and a 9mm -- were used in both shootings.

Two other men, Michael Brown, 21, of Hyattsville and Cotey Wynn, 24, of Neal Street NE, have been arrested and charged in the Trinidad shooting. They have not been charged in Myesha's killing, nor has Ross been charged in Givens's slaying.

Channing Phillips, a spokesman for the U.S. attorneys office, said that the investigation of both shootings is continuing and that he could not comment on the possibility of future charges against any of the three men.

The statements by the witness who identified Ross in the robbery would appear to give prosecutors a basis for exploring charges against him. The person told police that Ross was carrying a 9mm gun and that he could be overheard, after the robbery, saying, "I punished that dude," or something similar to that, according to the court documents.

But the witness also told investigators that he had considered participating in the robbery but opted not to, according to the court filings. That makes him a less-than-perfect witness for the prosecution.

Though the firearms evidence is compelling, it does not prove that any of the three men used the guns, which have not been recovered.

Ross, who was arrested July 28, was in court yesterday for a hearing to determine whether he should continue to be held without bond on the murder charge in Myesha's slaying. Detective Tony Patterson, one of the D.C. police investigators in the case, was the sole witness, and after the hearing, Judge Wendell P. Gardner Jr. ordered Ross back to be held without bond.

Myesha's killing was the 17th of a juvenile this year in the District, five more than in all of last year. It spotlighted the continued failings of the juvenile justice system.

Ross, who as a juvenile had been arrested and found to be delinquent, fled a group home, according to confidential records and a source familiar with his case. For more than two years, he was at large despite an outstanding warrant for his arrest, the source said.

And he was not alone. An ongoing investigation by the D.C. inspector general has found that little or no effort has been made to locate scores of juvenile delinquents who have absconded from group homes.

Myesha Lowe, in a family photo, was slain sitting in a car with friends.