Police investigating the fatal shooting of a roadworker in south Waikato say the half-hour leading up to the incident is crucial to the investigation.
George Taiaroa, 67, was killed while operating a traffic control point next to a one-lane bridge on Tram Road in the Kinleith Forest last Tuesday.
Police don't know how many vehicles travelled across the bridge in the 30 minutes before he was shot but say at one point a two-tone green vehicle came nose to nose with a tractor on the bridge.
Detective Inspector Mark Loper says the vehicle had to reverse because of a traffic control miscommunication and officers are keen to speak to the driver.
He says they're also still looking for a blue Jeep Cherokee.
Police have said that after Mr Taiaroa indicated to a four-wheel-drive vehicle that it should stop to let a logging truck cross, the truck driver saw him fall to the ground, while the four-wheel-drive headed towards Tirohanga Road.
Police believe it was not a random attack and are asking motorists who were in the area to come forward.
They want to speak to everyone who travelled through the area from 2.30pm that day until the shooting, which occurred just after 3pm.
Police seeking video footage
Detective Inspector Loper says it's possible some logging trucks or farm vehicles had security cameras on board that recorded images from the scene.
He told Morning Report police have a number of people in mind they want to speak to and the public is not at risk.
However, the call for possible cab camera footage may not come up with much.
National Road Carriers Association chairperson Steve Doughty says cameras in the cabs of commercial trucks are only triggered when something occurs, such as sudden braking or the truck crashing and rolling over.
A team of more than 30 officers is now working on the case.