He got confirmation from the vet yesterday that a tumour on Farris' heart caused his death.
"He was riddled with cancer, unfortunately."
Farris had not shown any signs of being unwell until the night before his death, so Mr Page hadn't known his pet and work colleague was sick.
He has had Farris for a little over two years, and said the dog was due to retire from police work in August, when he would be getting close to 8 years old.
Mr Page was due to replace Farris with Luke, a puppy he began training last year.
"I guess the silver lining for me is that I had Luke at the time. If I hadn't had another dog to concentrate on, it might have been harder to deal with."
Luke "probably couldn't care less" about Farris' passing but Mr Page had seen the younger dog going up to Farris' cage "almost like he's checking 'is he in there or not?' ".
"He gave him a bit of a hard time, actually. I didn't actually run them together."
Mr Page carried Farris' ashes yesterday and was taking the dog for his final ride in the police car, but was still trying to decide how best to farewell him.
His kids had suggested taking the ashes with him next time he went in the helicopter for a search and rescue job, and scattering them from the air. Another idea was putting them in a plant pot. "I haven't made up my mind."
Farris was known for his tracking ability and Mr Page said he particularly admired his "work ethic".
"Once he was on to something, he wouldn't stop searching." He spoke of taking Farris tracking for hours at a time and said while he wasn't an aggressive dog, he could be when it was needed.
News of Farris' death was posted on the Whanganui Police Facebook Page last week and had been shared nearly 100 times, with close to 200 people sharing their condolences in the comments.
"It's quite humbling, actually. ... it was quite satisfying to see all those good comments."
Mr Page hopes to be back on the streets with Luke as an operational team in November.