Ronan Kanda, 16, died after being stabbed in Mount Road near his home in Lanesfield near Coseley on June 29.
Prosecuting barrister Robert Price told the hearing in Wolverhampton that another suspect was now in custody and due to be questioned today.
"There is a suspect who was arrested and they are due to be questioned by officers today," Mr Price said.
No pleas were made and all three defendants, appeared by video link and spoke only to confirm their names and addresses.
Judge Michael Chambers QC set a trial date for April 24 next year and adjourned the case until September 19 for a plea and case management hearing.
The two 16-year-old defendants from Walsall cannot be named for legal reasons and were remanded in youth detention while Francis, of Rubery, Birmingham, who is also charged with possession of a blade, was also remanded in adult custody.