Betsy, a grey tabby cat, is suffering from tongue ulcerations and an eye ulceration, and was among the animals seized at the Toronto Humane Society's shelter on Thursday. (CBC)

Four animals inside the Toronto Humane Society's shelter in the east end of the city had to be euthanized after animal cruelty charges were laid against the president and the board of directors at the facility.

A puppy, two cats and a raccoon were euthanized overnight Thursday, said Alison Cross of the Ontario Society for the Prevention of Cruelty to Animals, or OSPCA.

The OSPCA alleges dozens of animals were neglected at the Toronto shelter, including dozens left to die in their cages without proper care and nutrition.

The River Street shelter is now closed and under the jurisdiction of the OSPCA.

Tim Trow, president of the Toronto Humane Society, sits in the back of a police car after his arrest. (CBC)

Toronto Humane Society (THS) staff are barred from entering the building as the Toronto Police and the OSPCA investigate the conditions at the facility.

In a further development, prior to a media tour of the shelter on Friday afternoon, OSPCA investigator Kevin Strooband told reporters his staff had found a dead cat caught in a trap inside the building.

He described the device as a live trap, meant to catch animals to transport them for humane purposes.

"This is pretty deliberate," Strooband told reporters. "Somebody set that trap and knew it was up there. But it wasn't checked until we received some information just now saying that there might be one up there."

Earlier Friday, Ian McConachie, a THS spokesman, was arrested as he tried to retrieve documents from the office. He was briefly detained before being released without a charge.

Shelter to open Tuesday

Around 1,100 animals are still inside and under the care of veterinarians, and will be put up for adoption Tuesday when the shelter reopens, the OSPCA said.

Five senior officials have been arrested and charged with animal cruelty after police conducted a Thursday afternoon raid:

• President Tim Trow.
• General manager Gary McCracken.
• Head veterinarian, Dr. Steve Sheridan.
• Supervisor Andy Bechtel.
• Manager Romeo Bernadino.

Charges against Trow, McCracken, Bechtel and Bernadino also include obstruction of a peace officer.

Members of the society's board of directors were also charged with five counts of animal cruelty, a provincial offence under the Ontario SPCA Act.

A Toronto Humane Society spokesperson called the OSPCA's actions disgusting and politically motivated. There has been a long-running feud between the two animal-care organizations, he said.

Euthanasia policy under fire

OSPCA lawyer Christopher Avery alleges the Toronto society is reluctant to euthanize sick or dying animals, and blames management for dictating euthanasia policy without taking the animals' best interests into account.

"What Mr. Trow did is he instituted a policy where the veterinarians, contrary to the regulations and laws that relate to veterinary medicine, aren't able to make the final decision with respect to their patients' medical care," Avery told CBC News.

"Euthanasia can only be approved by management, and management seemed more concerned with their euthanasia statistics because they use them for fundraising purposes as opposed to the best medical needs of the animals."

The society relies on donations as the sole source of its operating funds.

All five senior officials were released on bail late Thursday night. They are expected to appear in court in January.

With files from The Canadian Press