Neighbour Terry Gallavin told the Herald how a friend coming to visit him heard a heated argument between the pair about 8.30pm on Thursday.
"He said there was a big argument going on there, with a bit of screaming and yelling and swearing," he said.
"I didn't know what it was about - the first I knew of it was when they had all the cordon up there the next day."
On the same afternoon, Mr Gallavin noticed someone had kicked a hole in a panel fence at their property.
Another neighbour, Dawn Anderson, lived downstairs from their flat and was shocked to learn they had been implicated in the death.
"They sort of kept to themselves - you heard them and that was about all," she said.
"It's a reasonably quiet sort of neighbourhood around here as a rule, and it's sort of given us something to talk about. Something like that, you don't expect to happen."
The pair were being kept in custody until a court appearance in Rangiora tomorrow.
Less than 4km away, a police forensics team were continuing to canvas the area around the teenager's Barrington St house.
Christchurch police Detective Inspector Greg Williams said a member of the public found Jade's wallet on the rooftop carpark at the mall soon after 12.30pm on Thursday and handed it to the mall's management. "We have positively identified this wallet as belonging to Jade and are now making inquiries as to how it came to be at the mall, including reviewing security footage of the car park."
Mr Williams said the likely scenario was that something had happened to her by the time her wallet was found, and it remained unlikely she left her home on Thursday morning, when she was home from school sick.
Police have also been speaking with gardening contractors that visited the property to mow the lawns late that morning.
"Our focus remains on understanding what happened at Jade's home that morning," he said.
"We have a great deal of information already, which we are working through, and we are putting together a good picture of events."
Several people had contacted police in response to appeals for information about the movements of the stationwagon. "We've received a number of reports of sightings of the vehicle in the area of interest. These have been helpful in providing a more detailed picture of that car's movements on the Thursday morning.
"We are continuing to contact people who have called in with information, and we would still like to hear from anyone who may have seen the car."
One Barrington St resident, Vic Hunter, told the Herald the vehicle seemed unusual and had been seen "zooming" down the street.
Jade's parents, Gary and Tina Bayliss, have also asked people with information to come forward.
They said their family was devastated at the loss of their "beautiful daughter" and asked for privacy to help grieve.
The principal of Cashmere High School where Jade attended said the school community was shocked and saddened by her death.
Mark Wilson described Jade as an outstanding student with an exemplary school record whose motivation and hard work put her near the top of her class.
"She had a quiet and shy nature, yet was also a very friendly and positive person, who was held in the highest regard by all her teachers," he said.
"Our school students and staff will struggle to realise and accept that we have lost this delightful young person," he said.
A team of 35 police staff were working on the investigation through the weekend and the forensic examination work at the scene of the homicide was expected to carry on until at least tomorrow.
