A dog has died after he ate a sausage which had been laced with anti-freeze.

Bobby, a springer spaniel, died of acute kidney failure after eating a sliced Frankfurter sausage which was thrown over a garden fence in St Albans last Saturday.

His owners believe it may have been a targeted attack.

There have since been reports of dogs being targeted elsewhere in St Albans as well as near Radlett, prompting a warning from a vets.

Bobby, owned by Geoff and Sharon Kirby, of Firbank Road, was taken to the Royal Veterinary College in London on Monday after being violently sick.

He died on Wednesday.

Dog owners in the area have reported several cases of rat poison being left out over the past week - and many suspect that there may be a culprit on the loose.

A dog owner who lives in Harper Lane, between London Colney and Radlett, says she has found rat poison in her garden for the fifth time while Lee Field was walking his dog in Alban Way, St Albans, when he spotted six blue boxes of rat poison spread across the side of the pavement.

Mr Field said: “They were the same as I have in my bait boxes at work which are poison so I was certain they were.”

“From the way they had been left it looks sinister. They were not in one pile but had been spread out over a distance.”

“I'm hoping dog owners are being careful and watching their dogs when they walk them.”

Bobby’s owners have been left heartbroken by their dog’s death.

Mr Kirby said: "They told us to come and say goodbye. We had to come to terms with this, and we had to agree to stop his suffering."

"Bobby was everyone's best friend, no one had a bad word to say about him. I don’t know who would do this. Bobby had not upset anybody.

“But why was the Frankfurter sliced up?”

Marshalswick Veterinary Surgery says it has received reports within the last couple of weeks of dogs becoming seriously unwell and is urging dog owners to be vigilant.

“If your dog suddenly starts vomiting or develops dark spots on their gums, please take them to your vets immediately,” the surgery warned.

St Albans District Council is aware of the incidents and Hertfordshire constabulary is investigating Bobby’s death.

Anyone with information should contact 101.