Yogi, a great dane, mastiff and bull arab cross, was almost 10 weeks old when he disappeared from the airconditioned truck at 3pm on Friday, March 6, breaking owner Trent Cleal's heart and touching many more.
It sparked a mass search for the dog, with family, friends and strangers all wanting Yogi returned.
"I parked up in the turning lane on the corner of Ocean Reef and Motivation Drive, I had a truck with two trailers on, and walked across to the lunch bar by the Caltex," Mr Cleal, of Quairading, said.
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READ NOW"When I've come back, the passenger door to the truck's been opened and he was gone. It was a mixture of disbelief and heartbreak.
"Not trying to milk it but a very good mate of mine was on life support and the day I had to say goodbye was the day I went and got Yogi.
"It was a bit emotional; it still is."
Mr Cleal said the only way someone would have seen Yogi was from the footpath as he would not have been visible in the truck from the road.
"He'd have been standing on the passenger's seat with his paws up on the windowsill," he said.
In a bid to find Yogi, he has contacted the police, the RSPCA, local pounds, offered a reward, and created a Facebook page "Yogi is missing" to track down his "buddy".
"Everyone is pretty much exhausting every avenue they can and every time we see a dog that has the slightest colour of him, we stop and look," he said. "We've had about four or five (helpful tips), unfortunately they were dead leads but the one you don't chase is the one that will be him."
Mr Cleal said the support he had received was "amazing".
"It's certainly renewed my faith in people," he said.
Anyone with information can call Wanneroo police on 9406 2222 or Crime Stoppers on 1800 333 000.