Jagger, a 3-year-old Irish Setter, collapsed and died after leaving the show with a bellyful of poisoned beef, leaving his owners distraught and triggering a canine whodunit worthy of Agatha Christie.
The dog, also known as Thendara Satisfaction, died Friday shortly after returning to his home in Belgium from the Crufts show in Birmingham, England. A post-mortem examination found the poisoned slug killer cubes in his stomach, according to Jeremy Bott, one of Jagger's co-owners.
The only time Jagger was unattended and could have been poisoned was when he was on the stand for public viewing, his owners said - but they refused to believe that another competitor could have done such a thing.
"We can't and we won't think that this was the act of another exhibitor. If we thought this, we couldn't go on, and the last 30 years would be a complete waste," Dee Milligan Bott said on her Facebook page. "So I ask all of you to unite in finding the perpetrator who did this."
But that still leaves the question: Who would kill a dog show contestant and why?
Jeremy Bott thinks it was a case of mistaken identity. He said he believes the poisoner is someone who bears a grudge against dogs in general or the Crufts show in particular, but not Jagger himself.
In an article published in "Dog World," Milligan Bott suggested the real target of the attack could have been another dog she owns, Thendara Pot Noodle. That dog won the "Best of Breed" title at Crufts, while Jagger finished second in a preliminary competition.
Police in Belgium and Britain are aware of the incident, but authorities said they have not been asked to investigate. The Kennel Club, which organizes Crufts, said it is awaiting a toxicology report on Jagger's stomach contents before deciding what action to take.
Milligan Bott told reporters outside her home that Jagger's death shouldn't overshadow "the positive sides of Crufts."
"I certainly don't want our dog shows - the places we work so hard to get to - to become a ground of finger-pointing and suspicion," she said.
The Kennel Club issued a second statement Monday after reports that another dog had fallen ill after Crufts.
"The facts surrounding Jagger's sad death are still being established, and we must stress that any other unsubstantiated rumours about dogs being poisoned are just that," the club said. "There are any number of reasons why a dog may display symptoms such as sickness. And should a dog fall sick, there are vets at the show who will examine the dog in question and file a report."
No vets have raised concerns about poisoning at the show and "there have been no official complaints from any owners at Crufts 2015," the club said.
Canine competitions have long been the subject of rumours about unscrupulous behaviour - including owners slipping drugs to rival dogs. In 1996, a breeder was banned for giving valium to a Chihuahua at another British dog show.
And Crufts is not just any show. It is Britain's most famous dog event, attracting more than 21,000 competitors from 43 countries this year. It was founded in 1891, about 14 years after New York's Westminster dog show.
The stakes can be high. Although the prizes for such shows are small - the "Best in Show" title carries a purse of just 100 pounds ($150) - puppies from the winners can fetch thousands.
The grief of losing a beloved friend coursed through all the pictures and family statements Monday. The Botts placed a large image of Jagger on their website, his russet coat gleaming, his head held high. The photo was simply captioned: RIP Jagger.
The Botts, who run a dog breeding operation in England, were part owners of Jagger. The dog lived as a family pet with their co-owners in Belgium, where he visited retirement homes so elderly residents could pat him on the head.
For his Belgian owner, Aleksandra Lauwers, the pain was evident in a posting on her Facebook page.
"To person who has done it, hope you can sleep well knowing you have killed our love, family member and best friend to our son," she wrote.
Both families asked the media to leave them in peace to mourn.
"He was a typical Irish Setter, totally trustworthy and so loved," Milligan Bott told the BBC. "We are devastated."
Cook reported from Lauw, Belgium.