Before the teen was sent to Australia, the boy's mother had filed a formal complaint with police, alleging her son was having a sexual relationship with a minor. However, police decided against laying charges.
Under cross-examination by Dennis' lawyer Stephen Bonnar QC, the girlfriend's mum said she was concerned about her daughter having underage sex and the possibility of getting pregnant.
"I was very distressed, so was my husband," she said.
The court has heard that the teenage pair are still together.
As the teenage couple's families argued over the nature of the relationship, Dennis, a family friend and the police national Maori strategic adviser, organised a "mock arrest" to scare the boy off the relationship, the court has heard.
The teen was processed at the Auckland Central Police Station on May 5, 2015 as though he had been arrested by Dennis and Perry, the duty custody sergeant.
The court has heard that Dennis also gave the teen an ultimatum - to either go to Australia and start a new life or be charged for statutory rape.
The teen was then sent to Australia.
But on June 10, 2015 he tried to "escape" back to New Zealand.
His girlfriend's mum told the court that she helped organise for the teen to buy an airfare to Auckland.
But while her husband and daughter waited at Auckland Airport to pick up the teen she realised something was awry.
"It was taking a long time ... Myself and [my daughter] were liaising over the phone, an hour after the plane should've arrived - two hours," she told the court.
"Something's very wrong, he should have come through long ago," she recalled thinking.
The court has heard that Dennis "swung into action" after catching wind that the teen was on his way back to New Zealand.
The inspector contacted police at the airport and arranging for armed police to usher the teen off the aircraft.
Dennis told the boy not to come back to the country until he was 18 and placed him on another flight to Australia, the court has heard.
But once the teen was back in Sydney his girlfriend's mum made further plans to help "bring him home".
She flew to Sydney and helped him flee to a friend's home.
The teen also claimed he was being assaulted by relatives he was staying with in Australia and reported the incident to New South Wales Police on June 17, 2015.
Dennis, who was also the chairman of Te Puea Marae in Mangere, was stood down from his duties in September 2015 shortly after the teen laid a complaint.
Bonnar argues his client was trying to help the teen's family and was acting in accordance with Maori customs.
The trial continues.