Campbell has pleaded not guilty to aggravated robbery causing grievous bodily harm, committing burglary with a weapon and five counts of unlawfully possessing firearms.
The court has heard that three rifles, two shotguns and three air rifles were taken from Person's house in the attack. Two rifles and two shotguns were later found in a bivouac in a bush behind Campbell's mother's house at Tuai in the Wairoa District.
Crown prosecutor Clayton Walker has said the case against Campbell is circumstantial, built on several strands including the movements of a white van owned by Campbell's aunt and once registered to Campbell himself.
The court has heard a white or cream or pale-coloured van was seen at Person's property on the night of the attack.
On Wednesday, the jury was shown a slideshow presentation which tracked the the van connected to Campbell as it drove south from Tuai to Havelock North in the hours before the attack, and returned to Tuai in the early hours of the morning following it.
Its movements in both directions were logged both by roadside cameras and by signals from a cellphone which has been linked to Campbell.
Neal Richardson, a police manager who has not been involved in Campbell's case but who previously worked for Telecom and Spark for 33 years, was called to give technical evidence.
He explained how cellphones could be tracked using mobile phone networks.
Richardson said cellphones were still "actively communicating" with cellphone towers nearby, even when they were in idle mode. This was how the networks knew where phones were when they needed to direct an incoming call.
These connections were logged and police can access those logs by serving telecommunications companies with a "production order".
Richardson, in response to questioning from Walker, agreed that such orders are used "all the time" as an investigative tool by police.
In the case of Campbell's van, documents made available to the jury show that it was located 17 times by phones and cameras in the hours before and after the attack.
However, there is a nearly five-hour gap in the data which includes the time Person's home was invaded.
Richardson said networks cannot track a phone which is turned off. The log would show the phone's last location when it was active.
Campbell, cross-examining Detective Sergeant Craig Vining, asked if there were camera images which showed a vehicle heading towards Person's house at around the time of the attack.
"We did look at a number of cameras … there is nothing definitively," Vining said.
The trial continues.
