Police officers who shot dead a family dog in the street are facing allegations of racism and animal abuse.

Tiger, a four-year-old Staffordshire bull terrier cross, was allegedly stunned up to 20 times using Tazer guns and then shot up to four times after police said it was "aggressive" and a "danger".

But witnesses claim police were "overzealous" in their actions and racially abused a boy with Tiger before unnecessarily destroying the dog, who was cornered in a car park in White Horse Road, Croydon.

Tiger was being exercised by her schoolboy owner Jude Crossley, 16, and his friend Kamual William, 14, at 11pm on Tuesday, June 17. She had recently given birth to puppies.

Melvin Ashby, 47, who witnessed the killing, lodged an official complaint with the Independent Police Complaints Commission this week, claiming he had been disturbed by the chain of events.

Mr Ashby, who watched from his home opposite the incident, alleged police stunned the animal using the Tazer "many times", which caused it to run away.

He said officers caught the dog and then waited up to an hour before police marksmen arrived to shoot her.

He said: "The dog was calm although obviously distressed and I didn't see it attack a single officer. If it had, surely they would have needed medical treatment? What they did to that dog was inhumane and totally uncalled for. It was very upsetting."

His wife Lauren said: "I was upstairs watching from the window when I saw officers throw down one of the boys and shout racial abuse at him."

Jude Crossley, who attends St Mary's High School, said he was stopped with two of his friends by police officers.

During a search Tiger became agitated and police officers tried to "subdue" the animal with the use of a stun gun.

Jude said: "We were doing nothing wrong but walking my dog. The police jumped out of the van and were immediately aggressive towards us.

"They made Kamual get on the ground and called him a "Paki" and they searched me behind the van.

"Tiger, was very stressed and she had just had puppies so obviously she was anxious. I think she may have gone for an officer but it would only have been because of the Tazer or the fact they were hassling me.

"I was then put in the police van and that is when I heard shots from a gun. I knew that they had shot the dog because I could hear my friends shouting at the police after the shots rang out.

"It looked like Tiger had her head split open with a knife."

Kamual said: "An officer grabbed me by the throat with his hand, then they threw me to the floor. They left me lying face down on the floor handcuffed behind my back. I heard them shooting the dog.

A police spokesman said: "The Metropolitan Police Service (MPS) is to be passed a complaint in relation to the detruction of a dog. It would be inappropriate to comment any further on this incident at this stage.

"Any complaint of a racist nature will be thoroughly investigated. The MPS does not tolerate any form of racist behaviour and regards it as totally unacceptable."

A spokesman for the IPCC said: "We have received Mr Ashby's complaint.

"We have logged it and referred it to the Metropolitan Police who will decide if it is bona fide and deal with it accordingly."