A heartbroken family is offering a £1,000 reward after their beloved German shepherd dog was poisoned.

Harvey Singh, 22, of Dove House Crescent, Slough, said: “My dad went out to feed Sarasun and found him convulsing violently. We rushed him to the vet in Farnham Road who tried for four hours to save him, but it was no good.”

Mr Singh, a software development engineer, said his family was suspicious that it was something nasty and took the dog to the Queen Mother Animal Hospital in Hatfield, Herts for a post mortem examination, which revealed Sarasun had swallowed rat poison.

After scouring their CCTV footage the family spotted something being thrown over their garden fence shortly before Mr Singh’s father went out to feed Sarasun at about 4.50pm on Thursday, December 21.

The family believes they know why their dog may have been targeted.

Mr Singh said: “A spate of robberies and attempted robberies had occurred within the immediate area and we believe Sarasun had thwarted many attempts on not only our own property but neighbouring properties.

“We believe this to be a strong motive to target him in this cowardly way.”

Mr Singh said the whole family suffered a heartbreaking Christmas without six-year-old Sarasun.

He said: “We had had him since he was a puppy. He was not just a dog, we feel we have lost a family member. He never went without a meal or without a walk.

“That is why we are going the whole hog and offering a £1,000 reward. We believe someone may have seen something that might help police catch whoever did this.”

A police spokesman said: “We are investigating reports of a German shepherd being poisoned sometime between 4pm and 5pm on December 21. We would ask anyone with any information to contact police on 101 quoting reference number 43170380317.”

Ironically the crime is listed as ‘criminal damage’ - which is the only charge available to the police, even when a police dog is attacked. Campaigners are pressing for the law to be toughened.