On Monday it emerged a pit bull named Stella had been kept in a 3ft by 9ft cage for two years without exercise.
Now former kennel workers have released a video showing both Stella and a seized Rottweiler named Vinnie.
Devon and Cornwall Police said "immensely frustrating" delays in the judicial process left Vinnie in kennels for two years before he was destroyed.
The video, taken on the day Vinnie was put down, shows kennel staff playing with Vinnie while Stella, in the kennel next door, rubs noses with the Rottweiler through the metal mesh.
The BBC understands Vinnie had been trained as a guard dog and police said he was used to attack three people in 2013.
He was seized and placed in kennels but the court process took two years before a destruction order was carried out around 26 July 2015.
Former staff at the kennels say Vinnie had a "Do Not Enter" sign on his kennel and, as far as they were aware, was not let out for a period of two years.
Laura Khanlarian, who until December 2015 worked as an assistant at the private kennel used by Devon and Cornwall Police, said: "To move him from one cage to another he just went through the internal doors.
"He wasn't assessed like Stella so he really didn't leave the kennel at all.
"Vinnie had no contact until the day he was put down. I made that video an hour before when we were allowed in his kennel with him."
Another former worker at the kennel, who asked to remain anonymous, said: "Vinnie the Rottie had no human contact except being fed. He was deemed too dangerous to get out.
"But this was the dog that, once he knew you, wagged his tail, pushing himself against the bars, desperate for any attention.
"As far as I know he belonged to a man who trained him as a guard dog. Because he was possibly trained to bite we were told not to walk, go in with him, same as Stella as he was too dangerous."
Former staff at the kennels have told the BBC they offered to work with Vinnie and exercise him but were not given permission to do so.
After the BBC revealed Stella's plight, Devon and Cornwall Police Chief Superintendent Jim Nye said: "The welfare of dogs is extremely important to us.
"In the past year we have seized in the region of 100 dogs, and only Stella has been assessed as too dangerous and unpredictable for kennel staff to walk."
Following the release of the latest video, the force did not say if they or another body had ordered Vinnie - who is understood to not be among the last 100 dogs seized - to be kept without human contact.
However, in a statement they said: "Vinnie the Rottweiler was a dog seized and placed into kennels in 2013.
"Vinnie was a legal breed and was seized after it had bitten three people. Later the courts granted a destruction order on the dog who was put to sleep in the early to mid part of 2015.
"Within the last 100 dogs we have seized only Stella was deemed too dangerous to be exercised and instructions given to the kennel specifically in relation to this.
"It is important to stress that despite the very best effort of the police, the judicial process is not accelerated when a dog is placed in kennels. This is immensely frustrating for the police who hold animal welfare in the highest regard."
No-one from the kennels has commented.
A second dog seized by police was kept locked in kennels for two years without exercise, the BBC has been told.