Police found a piece of paper headed up "scenarios" in the glovebox of a car which they say shows plans to carry out an ambush and destroy a bridge.
Tame Iti, Te Rangikaiwhiria Kemara, Emily Felicity Bailey and Signer are on trial in the High Court at Auckland. They have denied charges of possessing guns and belonging to an organised criminal group with objectives including murder, arson and using guns against the police.
Giving evidence today, Constable Kate Perry said she found the document in the glovebox on the morning police raided properties in Ruatoki, Auckland and Wellington.
The Crown says the car was registered to Urs Signer and the document is in his handwriting.
Under cross-examination from Signer's lawyer, Chris Stevenson, Ms Perry said she also watched over a mother and her three children in a garage at the property where police found Signer's car.
She said the garage door was open but confirmed to Mr Stevenson that they were not free to leave.
Ms Perry watched the family for "some hours".
"It was a very comfortable garage. There were couches, seats and books."
She confirmed that one of the children was as young as five and the family had to stay in the garage for some hours while police searched their house.
Mr Stevenson asked if the mother was "upset".
Ms Perry responded: "She spoke to me and gave me their version of events."
Today the jurors were also shown a number of rifles and shotguns police seized in their raids.
Some of the rifles could have been turned into restricted military-style semi-automatics by loading them with the magazine cartridges also found by police, the court was told.
Police armourer Robert Ngamoki said he test-fired the guns and found them all to be in working order.
Some of the rifles and one of the shotguns had been cut-down. Under cross-examination from Iti's lawyer, Russell Fairbrother, Mr Ngamoki confirmed that hunters sometimes cut down their guns to make it easier to walk through the bush.
Earlier, the court was told that a bomb recipe was found in the flat of one of the members of the alleged military-style training camp.
Environmental Science and Research (ESR) fire and explosion investigator David Neale was asked to look at the recipe.
He said it gave instructions to make a thermite bomb. The explosion would not be a loud bang but would create a lot of light and heat.
"It can be used in many ways - to start fires, melt engine blocks and destroy pretty much anything."
He told Justice Rodney Hansen that thermite bombs were used in World War II to destroy trucks and artillery. The chemical process was also used to join tramlines together.
Kemara's lawyer, Charl Hirschfeld, asked Mr Neale if the thermite bomb would be used in "magic shows".
Mr Neale responded: "I wouldn't use it in a magic show because it burns very hot and spatters liquid metal around the place."
The trial continues.
* Firearms found by the police:
2 Australian rifles
Brown wooden Ruger
Baikal sawn-off shotgun