The male rough-haired lurcher was discovered wrapped in a red velvet curtain and blue towel in Jubilee Fields, off Cuckoo Lane, Hatfield.
The dog was so ill when he was found on Sunday afternoon he was unable even to lift his head.
Now the RSPCA has issued an appeal to find the evil owner – amid claims the dog had been used as ‘bait’.
RSPCA chief inspector Lynsey Harris said: “He was collapsed and had a deep, infected wound to his chest and multiple wounds all over his body, which were also infected. We don’t know how these injuries came about, but we think they were the result of him having been attacked by another animal, possibly another dog.
“Very sadly, he had to be put to sleep to end his suffering.
“There is no doubt that this poor dog suffered, and there is no doubt he was dumped in this out-of-the-way spot to die.
“He wasn’t wearing a collar and ID tag and wasn’t microchipped, as is required by law, so at the moment there is no way of us tracing his owner.”
Since the abandoned dog’s death, more than 1,700 people have signed an online petition calling for justice for the animal.
Petition author Wilson Milton said he thinks the animal had been used as ‘bait’.
He said: “He’s probably been used for bait, as he had a deep chest wound, blood all over his head and wounds all over his legs.
“The person responsible for this act of cruelty is still out there walking freely.
“Please join me in mobilising the authorities to look into this case and bring them to justice.
“Together we can make sure this poor baby gets justice and all it takes is to sign and share.”
The RSPCA said causing unnecessary suffering is an offence under the Animal Welfare Act and carries a maximum sentence of six months in prison and, or, a £20,000 fine.
* Anyone who saw anything suspicious in the area, who has any information about what happened to the dog or knows his owner should call the RSPCA inspector appeal line on 0300 123 8018 and leave a message for Tamsin Drysdale, who is leading the investigation.