NEW YORK - A young pit bull mix that survived being thrown off the sixth-floor roof of a Brooklyn building still was not fit to live because of her aggressive behaviour, her caretakers said, and she was euthanized Friday, despite pleas from animal activists to spare her life.

Oreo suffered two broken legs and a fractured rib when she was beaten and thrown off a roof June 18. After months of working to rehabilitate her, the American Society for the Prevention of Cruelty to Animals determined that she was unpredictably aggressive, and could never live among humans or other dogs.

The plight of the 1-year-old Oreo stirred emotions among animal lovers, and the ASPCA decision to euthanize her led many to flood the organization with hundreds of calls, emails and Twitter messages.

"We're saddened by the outcome," said ASPCA spokesman Andy Izquierdo on Friday afternoon after the organization announced Oreo's death. "But we truly feel it's the most humane decision for Oreo."

Earlier, Izquierdo said the agency had received well over 200 calls and email messages, as well as at least two death threats.

"People don't know the behavioural piece," Izquierdo said. "We could fix her physically, but we couldn't do anything with her psychologically."

Protesters rallied outside the building Friday morning. And at least one pet sanctuary offered to take in the dog.

"The aggression thing is a dumb excuse because all dogs can be worked with," said Emily Danks, a self-described animal rescuer who said she was escorted out of the ASPCA's building on the Upper East Side after trying to convince staff members to let her take Oreo.

She said she had planned to take the dog to Pets Alive, a sanctuary in Middletown.

Matt DeAngelis, executive director of Pets Alive, said his organization had left phone messages for the ASPCA with an offer to take in Oreo. But he said they had not heard anything, and he was perplexed at why the ASPCA didn't accept the group's offer.

In an email, Stephen Zawistowski, one of the ASPCA's lead animal behaviour experts who had worked with Oreo, said the organization didn't believe that sanctuary placement was "good for her welfare."

"We made this decision having the experience of working with a number of well-known sanctuaries and rescue groups," he said, adding that the ASPCA was unfamiliar with Pets Alive.

Fabian Henderson, a 19-year-old who lived at the housing complex in Brooklyn's Red Hook section, where officers found Oreo badly injured, was arrested on felony charges. He has pleaded guilty to aggravated cruelty to animals, and is to be sentenced Dec. 1.

There was no phone listing for Henderson at the Brooklyn building. His lawyer could not immediately be reached for comment.