Cassandra Jade Mann, 61, faced Mackay Magistrates Court and was found guilty of stealing a dog and injuring it by getting it desexed by a vet.

Cassandra Jade Mann, 61, faced Mackay Magistrates Court and was found guilty of stealing a dog and injuring it by getting it desexed by a vet. Luke Mortimer

A BLACKS Beach woman who found a lost dog, claimed it as her own and then got it desexed has been convicted of stealing and injuring an animal in a bizarre court case.

Cassandra Jade Mann may have gotten away with the theft and "maiming" of the animal, had the vet who performed the surgery not stumbled on a registered microchip while implanting a new chip in the small tan and white dog named Ty.

Ty was later euthanased after being returned to his owner, perhaps because he had been desexed, prosecutor Acting Sergeant Duncan Erskine told Mackay Magistrates Court.

Mann, a 61-year-old disability pensioner, faced the court yesterday to hear she'd been found guilty by Magistrate Mark Nolan after a summary trial.

Mr Nolan said Mann told the court she'd found two dogs - Ty and a larger white dog, Cooper - on January 27, 2017 at Blacks Beach.

Mann said she believed both collared dogs "had been abandoned".

She claimed to have repeatedly called a number on dog tags unsuccessfully, Mr Nolan said.

"The defendant also told the court she made up huge signs with the dog's names... which she says she displayed around the area... ," he said.

Several days later, Mann "decided to keep the smaller dog", claiming she was convinced they had been abandoned.

After a call from Mann, a Mackay pound employee retrieved the larger dog and it was reunited with its owner - the partner of Ty's owner.

"As to why the defendant did not tell the person from the pound that she had, in fact, two stray dogs ... the defendant says that by then she decided she was going to keep the dog Ty and chose not to mention that fact," Mr Nolan said.

"She says she did this because she feared the dog would be placed on death row if he went to the pound."

Mr Nolan labelled Mann's evidence as "entirely unconvincing", noting she could have tried to find Ty's owner through the pound.

The two dogs involved in the court case against Cassandra Jade Mann, Ty and Cooper. Facebook

Days later, Mann took Ty to a vet clinic with a new collar, signing off on a consent form as the dog's owner to get him desexed and microchipped.

Mr Nolan said the vet had the belief "the dog's owner had consented".

"After the surgical procedure was completed a microchip was implanted... the dog was scanned to check the placement of that chip and it was during this scanning that a second microchip was discovered to be already in the dog."

The clinic contacted Ty's owner, and Mann's actions were uncovered.

Mr Nolan said Mann "directly caused maiming of the dog by the castration surgery".

Mann said she suffered mental illness, but Mr Nolan noted little evidence.

Mann also pleaded guilty to assaulting police - for taking her bra from under her shirt and throwing at an officer on July 27, 2017 - and failing to provide a specimen of breath when required to undergo a breath test for suspected drink-driving on August 3, 2017.

Mann was sentenced to nine months probation, and disqualified from driving for nine months for failing to provide a specimen.