Police are seeking a vehicle seen parked up near where George Taiaroa was shot dead shortly before it happened.
The roadworker was killed at Atiamuri in south Waikato two weeks ago.
Police said today a dark-coloured 4WD believed to have been parked on a nearby road before the fatal shooting was of interest to the investigation.
A farmer travelling in a tractor on Ongaroto Rd from Whakamaru towards Atiamuri on the afternoon of March 19 told police he saw the 4WD parked on the road and it later travelled behind him on Tram Rd towards a traffic controlled point manned by Mr Taiaroa.
The 4WD did not try to pass the tractor and appeared to drop back as it neared the traffic control point, resulting in the vehicle being stopped by Mr Taiaroa, said Detective Inspector Tim Anderson .