An Instagram beef among feuding teens may have led to the October slayings of two high school students in South Philadelphia, a crime that stunned the city, devastated several families, and for weeks left a neighborhood on edge.

But just as prosecutors unveiled the possible motive in court Wednesday, their lone witness — a 15-year-old who is friends with the accused killer, Brandon Olivieri — suddenly turned hostile, refusing to answer their questions and testifying that his initial statement was full of lies he told police or fabrications by detectives.

The striking turn of events came during the preliminary hearing for Olivieri, 16, charged with fatally shooting Salvatore DiNubile and Caleer Miller, both also 16.

Brandon Olivieri
Philadelphia Police Department
Brandon Olivieri

Judge Patrick F. Dugan ordered Olivieri held for trial on all counts, then punctuated the morning-long hearing with a thundering soliloquy about the toxic mix of teens, violence, and easy access to guns in Philadelphia.

"When the hell are we going to stand up in our society and stop this crap?" he said.

The proceeding was the latest development in one of the year's most shocking crimes, a case that sparked retaliatory violence against Olivieri's family home and spurred hundreds of mourners to attend memorial services for both DiNubile, a junior at St. Joseph's Preparatory School, and Miller, a junior at a Mastery charter school.

The courtroom was packed with friends and relatives of Olivieri, DiNubile, and Miller. The families declined to comment afterward, although a DiNubile family spokesman, Frank Keel, said they were still reeling from their unexpected loss.

Olivieri, wearing a black T-shirt, sat with his hands clasped and displayed little emotion during the hearing.

The lone witness to testify, a high school sophomore, repeatedly declined to answer questions from Assistant District Attorney Carlos Vega, leading the prosecutor to read from the statement the witness allegedly gave to police days after the crime.

The Inquirer and Daily News are not identifying the witness due to the sensitive nature of the case and because he is a juvenile.

The narrative presented in the statement painted a tragic portrait of a trivial teen feud gone wrong, with Olivieri, Miller, and the witness – all of whom were friends – walking around South Philadelphia after school Oct. 24, looking to fight with people they had been sparring with on Instagram. The statement did not specify what the feud was about.

The teens couldn't find their first set of potential targets, according to the statement, but they eventually made their way to 12th and Ritner Streets, where Olivieri pulled a gun on DiNubile, then shot him and accidentally shot Miller during a scuffle while the witness ran away.

Both DiNubile and Miller were declared dead that night.

The witness allegedly told police that he and Olivieri, a student at SS. John Neumann and Maria Goretti High School in South Philadelphia, later went to the home of another friend's grandmother to avoid being picked up by investigators. He also told police that Olivieri was the shooter, and identified him in photos and surveillance videos, according to his statement. Prosecutors also read text messages he allegedly exchanged with Olivieri in the days after the crime.

But the witness testified that most of that information was either a lie or concocted by detectives. Olivieri's defense attorney, James Lammendola, sought to portray the witness as being scared of police, prosecutors, and even his own lawyer – willing to say anything to appease them and avoid being charged with conspiracy or other crimes.

William J. Brennan, the teen's attorney, said such allegations were "wildly irresponsible."

"Any suggestion that there was intimidation is ridiculous and a rank obscenity," Brennan said in an interview after the hearing.

The teen now faces a court hearing of his own: Because of his refusal to answer dozens of Vega's questions, a judge will have to decide next month whether to hold him in contempt of court.

Olivieri remains in custody without bail while awaiting trial. A date has not been set.