The car pulled up next to them again.
"They came back and pulled the gun out. I thought it was a fake. That's why I didn't run."
Amosa approached the car and that's when one of the men started shooting.
The three boys were shocked and didn't have time to react. After the shots rang out the car sped off and the victims ran home.
The boys were bleeding. One had bloody wounds from the shotgun bullet sprayed across his cheek and neck.
The other had similar wounds over his arm. Amosa had a small injury to a finger.
The whole family had vacated the house to avoid further trouble. Amosa said he has seven cousins who live there and the youngest is just a baby.
"There was too much blood ... I love those boys. It breaks my heart seeing them like that.
"It makes me scared for my family. I'm scared they [the offenders] might come to the house."
Amosa hoped police would catch the men. He wants the offenders to know that they "shouldn't bring a gun to a fistfight".
He said the car occupants were Tongan and from the 36 and Killer Beez gangs.
Amosa, who is Samoan, said there was rivalry between Samoans and Tongans in the area.
Acting Detective Senior Sergeant John Love said two of the victims had now been discharged from hospital and one remained in hospital with non-life threatening injuries.
Police were continuing their investigation into the shooting, he said.
He said a confrontation was believed to have taken place shortly before the shooting near the Ferguson Rd shops.
There were believed to be three offenders in the vehicle who were yet to be found.
Police were speaking with victims and neighbours who may have witnessed the shooting or the prior altercation as well as reviewing CCTV footage.