WA teen behind bars over Kuol's death

A teenager who threw a brick at a boy during a brawl outside a Perth party, killing him, has been sentenced to six years behind bars.

The boy, now aged 18, had pleaded guilty to the manslaughter of 17-year-old Sudanese-born Kuol Akut.

In sentencing him on Friday, WA Children's Court president Denis Reynolds described it as a "classic example of peer group pressure".

"Regrettably, loyalty and wanting a sense of belonging can result in a person, and particularly a young person, engaging in serious anti-social behaviour," he said.

"The deceased at no time did anything to you."

Judge Reynolds said although the brick was not aimed directly at Kuol, it was a deliberate act.

"What you did was extremely reckless," he said.

"I'm satisfied that you were nevertheless frightened, and that contributed to your poor judgment."

Judge Reynolds described Kuol's death as a "tragic and senseless loss", but accepted the offender was remorseful.

He also referred to victim impact statements from Kuol's father, who described feeling fear and loneliness at losing his best friend.

Kuol's mother also described emotional trauma, stress, anxiety and sleeplessness, and feeling that life no longer had meaning.

Judge Reynolds noted the offender had a supportive family, did not have a record and was a good student.

As he was led away, the offender's supporters shouted: "We love you!"

Outside court, his father told reporters the family was very sorry and devastated by what happened.

"I know it's not going to calm what they're going through, but I'm just hoping that now that my son has been sentenced that we can all move on," he said.