Joshua Horton, 20, was charged with murder, accused of stabbing 17-year-old Maaka Hakiwai in the heart with a knife and his older brother Nathaniel twice in the leg, at Kings Park in September 2019.
A jury this afternoon found him guilty of the lesser charge of manslaughter, and intention to cause serious injury.
CCTV footage shows Mr Hakiwai and his brother Nate in their final moments together leading up to the attack.
They were walking down the street and were at a bus stop when a car pulled up and two strangers got out and came after Nate’s Philadelphia 76ers NBA cap.
In court, Horton seemed relaxed after the verdict was handed down.
Horton’s lawyers asked for him to be seen by a psychologist in prison.
Prosecutors said a number of victim impact statements will be submitted from Mr Hakiwai’s family, who were not present in court today.
They will be heard at the pre-sentencing hearing in June 21.