Police have questioned a man in relation to the second serious assault against police in a month in Ngaruawahia which left an officer unconscious and bloodied.
But they were last night no closer to knowing who the Good Samaritan that called them on the injured officer's radio was.
Huntly sub-area
manager senior sergeant Pete Simpson said the man being questioned was found yesterday at a Ngaruawahia house not far from where the officer was attacked on Wednesday about 9.30pm.
The officer was responding to a disorder call and was awaiting backup when he was alerted to a man described as "out of control".
Details of what happened next were unclear but someone implored the officer to intervene.
He was struck down a few metres from his vehicle shortly after he got out of his car, hitting his head on the kerb as he fell.
Mr Simpson said an unidentified bystander used his police radio to call for help and officers arrived to find their colleague bleeding and unconscious.
"We're very grateful for that person's actions," he said.
Yesterday, several police officers continued their investigation, combing a large, cordoned-off part of the street.
Neighbours said the street was usually quiet and a good place to bring up children although many residents rented homes and were transient.
Neighbour Chris Staples, who has lived on Newton St since 1976, said the latest incident was out of character for Ngaruawahia, despite a serious attack just around the corner from his property in which one police officer was hit over the head with a pool cue and another struck with a bottle by a youth less than a month ago.
"Things like this are out of the blue around here - I've lived here for years and only once had petrol stolen from my car," he said.
The officer is recovering at home and has little memory of the attack.
Waikato Deputy Mayor Clint Baddeley said both attacks were deeply concerning.
