The dog was awarded the People's Dispensary for Sick Animals (PDSA) Gold Medal in 2016 for his role in the fight against anti-poaching in SA.
De Beer said Killer had been one of the first dogs used in the Kruger National Park. Since 2011, he had arrested close to 200 poachers.
“Killer served the Kruger National Park up to last year and we decided not to deploy him that much any more and let him rest a bit,” he said.
Amos, who was his handler, was present to say goodbye, having spent many years and developed a bond with Killer.
“Killer left a big gap in our lives. We will always remember killer as a hero he was for the rhinos, the fight against rhino poachers,” he said.
Killer was expected to be cremated soon, after which a memorial service would be held and his remains placed in a safe place.
“Rest in peace, Killer, you will be sorely missed,” added De Beer.