The bull breed-type dog was discovered by a member of the public in Cheney Row Park, on September 5 between 4pm and 6pm.
Nicola Thomas, an animal rescue officer with the RSPCA, said: “We’re grateful to the member of the public who found this poor dog and sounded the alarm.
“Sadly, there were no identifiers at all – no chip, collar, lead, or anything, so we’re urging anyone with information to come forward.
“The circumstances in which this dog’s body was found are clearly a potential cause for concern, and we are looking into what may have happened here.”
The black and white male dog was found without a collar, lead, or harness, and had no microchip.
The body was already badly decomposed, the RSPCA said.
The charity has asked anyone who may have seen anything suspicious or who has information about a large bull breed dog in the area to contact its inspectorate appeal line.
This incident comes after serious acts of animal cruelty were highlighted as part of the RSPCA’s Summer Cruelty Appeal.
Last September, the RSPCA received 1,989 calls about animal abandonments across England and Wales.
Ms Thomas said: “Summer should be a season of joy for animals.
“But there’s a side to summer you don’t see.
“For thousands of animals, it’s a season of pain, fear and suffering, when cruelty peaks – which is why we’ve been so grateful to everyone who has supported our Summer Cruelty Appeal this year.”
Anyone with information about the dog found in Cheney Row Park is asked to contact the RSPCA’s inspectorate appeal line on 0300 123 8018.
More details about the charity’s work and how to support its campaigns are available on the RSPCA website.