The RSPCA is investigating the poisoning of three cats which left the young animals fitting and one howling in agony before they had to be put down.

All of the cats, belonging to Joanne Eastwood, of Cambridge Street, Queensbury, digested anti-freeze which can lead to vomiting and seizures and be fatal for cats. She believes the cats were targeted by people who wanted to kill them.

The suffering of the pets was so great that the vet was moved to tears when the third animal was taken to be put down, Miss Eastwood’s partner, Darren Bowling, said.

“I was absolutely devastated and angry. It’s bad enough losing a pet in normal circumstances or in an accident, but to know somebody’s maliciously gone out to kill an animal, it made me really angry,” Miss Eastwood said.

The attacks follow similar incidents in Eldwick in May where five cats drank anti-freeze, killing four of them.

Now Miss Eastwood wants to warn other pet owners, and said she is frightened to let her other cats outside.

The 44-year-old was making dinner when she noticed two-year-old Annabelle acting strangely.

“I picked her up and she just looked like she’d been drugged. She was alive, but it looked like she didn’t know where she was. I’ve had cats for six years and I’ve never seen anything like this,” she said.

Later, the mother-of-two noticed another pet was unwell.

“My other cat, Will, was acting strange and on the ground.”

She called the PDSA who advised her to take the cats for treatment at its centre in Bradford.

That evening vets did blood tests and found both cats had anti-freeze in their system.

When she returned home, at about midnight, she spent hours searching for another of her cats, Gus, who had gone missing. She managed a couple of hours sleep before finding him just after 5am howling in agony in a neighbour’s garden.

“Because the anti-freeze had been in his system much longer, he was much worse,” Miss Eastwood said.

RSPCA wellbeing co-ordinator for the north of England Leanne Plumtree said: “The incident has been tasked to an RSPCA officer to look into and anyone with any information should call 0300 1234 999 and ask to leave a message for inspector Sarah Bagley.”