As many as nine dogs were found Thursday morning in the basement of a West Side apartment building along with a book on dogfighting and what "appeared to be a dog treadmill," Chicago police said.

The dogs were found in cages after firefighters responded to a small fire at the site, said Officer Laura Kubiak. But despite the discovery of the dogfighting paraphernalia, Officer Marcel Bright said it's too early to tell whether the dogs were used for fighting.

One of the dogs appeared to have a snout injury, but the others did not appear to have serious injuries, police said.

Police said nine dogs, three of which observers at the scene said appeared to be pit bulls, were seized at the scene by the Chicago Commission on Animal Care and Control. But Mark Rosenthal, operations manager for the commission, said he was aware of seven or eight dogs that were seized along with a parrot.

Three of the dogs that Rosenthal saw appeared to have scars on their bodies, but he could not say whether the scars were consistent with dogfighting. Rosenthal said that will be determined when they are examined by a veterinarian.

"We're holding[all the animals] pending the police investigation," said Rosenthal.

A small electrical fire broke out in a first-floor unit in the building in the 3400 block of West Harrison Street about 5:30 a.m., according to fire officials. No people were hurt.

The blaze prompted firefighters to go to the basement to turn off the power.

"The renter [of the burning unit] did not have access to the basement. That's why we had to force entry to the basement," said Larry Langford, a Fire Department spokesman.

Because they had to force their way down there, fire personnel called police. And when firefighters entered the basement, they saw the dogs in their cages, Langford said.

Police were trying to locate the owner of the animals.

jgorner@tribune.com