A Perth woman has been found guilty of unlawfully killing a teenager and injuring four of his friends after running them down following a street fight between two groups of youths.

Key points: The incident began when two groups of youths organised a fight

The incident began when two groups of youths organised a fight Aya Hishmeh's younger brother and sister were subsequently injured

Aya Hishmeh's younger brother and sister were subsequently injured She later ran her car into a group of youths she thought was responsible

But Aya Hishmeh was found not guilty of murder and four counts of attempting to kill the boys after a trial in the WA Supreme Court.

Hishmeh, 23, has been on trial for the past three weeks over the death of 17-year-old Jacob Cummins on Eucalyptus Boulevard in Canning Vale in December 2017.

She admitted to a lesser charge of driving dangerously causing death and bodily harm, but denied five more serious charges she faced.

Jacob Cummins died after he was struck by the car on Eucalyptus Boulevard in Canning Vale. ( Supplied: Family )

Jacob and four other teens were run down by Hishmeh, who the court was told was angry after being told her younger brother and sister had been injured in earlier incidents.

That included a fight in a park between school students in which Hishmeh's brother was punched.

After hearing about what happened to her brother Hishmeh and some of her relatives went to a nearby McDonalds where there was further violence and Hishmeh saw her sister with a slashed arm.

Witnesses testified they heard her say she was going to kill the teens she believed responsible before getting into a high-powered car and driving at speed through the suburban streets.

It was estimated she was driving at 78 kilometres per hour at the time she ran into the group of teenagers.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 49 seconds 49 s Helicopter footage shows the aftermath at the scene.

In emotional evidence, Hishmeh maintained she had not intended to kill or hurt anyone, arguing the crash happened because she lost control of the car.

The jury deliberated for three-and-a-half hours before announcing the verdicts, finding her guilty of one count of manslaughter, three counts of causing grievous bodily harm and one count of doing bodily harm.

She has been in custody at Bandyup women's prison since her arrest on the night of the incident.

She was remanded in custody until she is sentenced in April.