A lawyer for Brandon Olivieri, the teenager accused of fatally shooting two 16-year-olds during an argument last week in South Philadelphia, said Monday that the youth denies the charges, and that he was "very good friends" with one of the victims and would have no reason to shoot him.

"There's no motive here at all," attorney James Lammendola said. "There's no motive whatsoever, as far as this case [is] concerned."

Police and court documents support the contention that Olivieri, 16, was friends with Caleer Miller, one of the two shooting victims last Tuesday. Authorities contend that Olivieri shot the other victim, Salvatore DiNubile, during a dispute involving at least five teens at 12th and Ritner Streets, and that a stray bullet struck Miller in the chest.

The new details provide a partial glimpse into an incident that shocked the city and has led to vigils, funerals, and even retaliatory violence against Olivieri's family home. Still, many questions remain unanswered, such as what the teens were fighting over, or how any of them would have been able to obtain a gun.

Lammendola said that he spoke briefly with Olivieri on Friday, when Olivieri surrendered to police, but that he hoped to speak to him again in the coming days.

Homicide Capt. John Ryan on Monday declined to provide specifics on the events that precipitated the shooting. Relatives of DiNubile and Miller have not spoken publicly about the crime.

DiNubile was a junior at St. Joseph's Preparatory School, and Miller was a junior at Mastery Charter School Thomas campus. Hundreds of mourners attended separate vigils for the youths last week.

Court documents say at least five teens gathered on the 2300 block of South 12th Street around 8:30 p.m. Tuesday. Ryan said the members of each group knew one another but declined to elaborate.

According to court documents, at least one other person was with DiNubile during the confrontation, and another person was with Olivieri and Miller at the time.

After a brief conversation, the documents say, Olivieri pulled a .45-caliber handgun from his waistband. DiNubile reached for the gun and struggled with Olivieri, the documents say, but three shots went off. One hit DiNubile in the chest, and another struck Miller.

Both teens were declared dead within an hour. Olivieri, meanwhile, tucked the gun into his waistband and ran away, according to court documents.

Police have not recovered a gun, or said how a 16-year-old would have obtained it.

Lammendola said the same type of handgun was used to shoot up Olivieri's family's house early Friday. Police said 14 shots were sprayed into the family's home, on the 1600 block of South Juniper Street after a police officer tweeted out information identifying Olivieri as a suspect.

Two people were home at the time but no one was injured. Police said Monday that no one had been charged in the incident.

Thousands of people mourned DiNubile at a funeral this weekend in South Philadelphia. Miller's funeral, meanwhile, is scheduled for Saturday morning at Love Kingdom Fellowship Church in Queen Village.

Staff writer Colt Shaw contributed to this article.