Published Sunday, 09 September 2012
The pet suffered horrific injuries after it was doused in a flammable liquid and set alight in the Maghaberry Road area on Sunday 26 August.
A message from the Agnew family on the 'Justice for Cody' Facebook page said her condition had been getting worse since Friday.
"Bad news , Codie didn't make it," they wrote.
"She had been getting worse from Friday and the vets had tried everything they could. We are all gutted, but we know she was suffering and was only going to get even worse."
Cody had been receiving treatment at the vets and was making progress with the help of strong pain relief medicine.
An online fund was set up by well-wishers who had raised over £2,300 towards her vet bills.
David Wilson of the USPCA said: "I'm very sorry to hear that animal has perished after the suffering that she has gone through despite the best of veterinary care.
"It would indicate that there are sick people in Northern Ireland society who would carry out deeds like that, very concerning and shows a total lack of compassion.
"For a family pet to be lost, maybe children in the house, it is a shocking thing. It's a bereavement within the family."
Two men, both aged 21, were arrested in connection with the attack.
They have been released on police bail pending further inquiries.
Police released a statement calling for calm following an influx of comments on their Facebook page, adding that they are continuing to investigate the case.
"After hearing the tragic news that Cody has been put to sleep, we would like to remind everyone that Police are dealing with the matter, and two people have already been arrested," said PSNI Lisburn on Saturday.
"All evidence takes an amount of time to process, and when the investigation is complete the matter will be forwarded to the PPS.
"We would appeal for calm and remind everyone that bad language or threats on this page will not be permitted in any form."
Meanwhile over 60,000 supporters on Facebook and Twitter have condemned the attack and offered their condolences to the Agnew family.
© UTV News