Dog wardens were alerted to the dead Staffordshire bull terrier on Monday, March 11.
The dog, a female, had been dumped in a pale blue suitcase.
The Leeds City Council Dog Warden Service said that they believe she had suffered before her death.
-> Leeds man steps in to help rough sleeper who lost everything in tent fireIn a statement on Facebook, they said: "Yesterday morning dog wardens were alerted to a dead, female, Staffordshire bull terrier (brindle) in Rein Park, Seacroft, LS14.
"The dog had been dumped in a pale blue suitcase. The circumstances and condition of the animal leads us to believe that it may have suffered prior to it’s death.
They also said the dog had been microchipped but the details registered to the dog are out of date.
Now they are appealing for any information about the dog and asking anyone with details of the incident to contact the Dog Warden Service on 0113 2224406.