Mr Page said Luke found the man and ended up "basically standing on the guy", who was lying on the ground.
"As soon as I chucked in a 'Good boy' ... he was really focused on the offender."
Now, instead of rolling on the ground in excitement, Luke would bark at the people he found.
Mr Page and Luke sat the test to become operational in November and hit the streets a week later.
Only two hours into their first shift Luke made his first catch - three shoplifters.
They were able to catch some burglars in the same week, Mr Page said.
He began training Luke last year, because his dog at the time, Farris, was approaching retirement.
But exactly a year ago Mr Page opened Farris' kennel and found his companion had died overnight.
At the time he counted having Luke to concentrate on as a silver lining to a dark cloud.
He will be able to see Farris in action again on April 6, when a Dog Squad episode on television will show him and Farris on the job together.
"I don't get emotional about it," Mr Page said. "It's cool seeing him."
After Farris died, helicopter pilot Dean Lithgow got in touch with Mr Page and offered to fly him and his family somewhere to scatter the dog's ashes.
They flew to Lismore Forest and landed beside a lake where they spread the ashes.
Working with Luke was a bit different to working with Farris.
"Farris was really, really laid back and chilled, whereas Luke, like my first dog ... he's just quite manic with the toys.
"That's his world ... his world revolves around chasing toys.
"He's just showing his level of drive. We don't knock that, we like that."
Since he and Luke became operational, Whanganui has had a full police dog team.
Mr Page said it would probably be another year before Luke got in the "groove".
"We use the term 'hit their straps'."
Mr Page said dogs started to know what they were doing when they reached 3 years old.
-The Dog Squad episodes showing Mr Page and Farris air on April 6, May 11, and May 18.