A 13-year-old boy has been arrested on suspicion of murder as the investigation into a fatal street stabbing continues.
The youth handed himself in at a police station on Monday night, West Midlands Police said.
It marks the fourth arrest in connection with an investigation into the death of Ozell Pemberton.
The 16-year-old was stabbed once in the heart during a fracas outside McDonald's in Sutton Coldfield town centre, Birmingham, on Thursday afternoon.
Another male youth, aged 17, appeared at Birmingham Crown Court over videolink on Tuesday charged with Ozell's killing and is due back in court next month.
He is set to stand trial for the murder in October.
Meanwhile, a 21-year-old man who had been detained as part of the inquiry has been bailed pending further enquiries.
Another 17-year-old male is still being questioned.