Aspiring rapper Kelyan Bokassa was fatally stabbed as he travelled home on a route 472 bus on January 7.
He had been sitting on the back seat of the bus on the upper deck when the two youths came at him with “lengthy machetes”.
The youths, now aged 16, appeared to have been tipped off that Kelyan was there before they boarded the bus and walked directly towards him, the court was told.
They will be sentenced at the Old Bailey by Judge Mark Lucraft KC today (July 25) from 2pm.
At an earlier hearing, prosecutor Tom Little KC had said: “It is clear this is not a form of spontaneous incident. The two defendants must have known the deceased was on the bus.
“They approach him and almost instantaneously the two of them pull out machetes and attacked the deceased.
“He is stabbed or attempted to be stabbed on a total of 27 occasions before the defendants made their way off the bus.”
Emergency services were called to Woolwich Church Street, near Woolwich Ferry, just before 2.30pm.
Kelyan had sustained a severed femoral artery and died shortly after medics arrived at the scene.
One of the machetes was discarded in the River Thames, but later recovered.
In an unusual move, Scotland Yard had issued CCTV images and named two boys as part of a public appeal for information.
They were arrested on January 15 after a manhunt by Met officers, and charged the next day.
The pair went on to plead guilty on May 23 to Kelyan’s murder and having a knife on Woolwich Church Street.
