Tonga's police commander says speed was the key factor in a road accident on Tongatapu in which four teenage boys were killed last Friday afternoon.
Chris Kelly says all the country is mourning the deaths that didn't need to happen.
He says a car carrying six teens, who had just left their school graduation ceremony, went out of control during an overtaking manoeuvre, and hit a tree.
"It was clear from our enquiries, and we have interviewed the driver of the other vehicle plus a couple of witnesses who were walking nearby, that speed was a factor, along with the lack of use of seat belts, but certainly it has had a terrible impact here. It has raised our road to 12, all in one hit, and certainly the community is mourning the loss of these young men, which I think, quite frankly, didn't need to happen."