A community constable is extremely thankful to a member of the public who helped catch a young teenager after a knife was allegedly held on him.
The constable had picked up two young people from a home in Onerahi on Wednesday at 4.45pm when he noticed another teen near Onerahi Park.
Whangarei police spokeswoman Sarah Kennett said the constable stopped to pick the boy up and, while he tried to take the boy home, another group of teenage boys who were around started "acting up".
One allegedly pulled a knife on the constable.
"The constable backed off and called staff, who arrived quickly," she said.
When more police arrived, some of the teenagers ran off.
A man who was driving past at the time noticed what was happening and pulled over to help.
The man got out of his car, chased one of the boys and caught him - an act that the police are thankful for.
Two 13-year-old males are being dealt with by Youth Aid.