Breeder of ‘Killer Kimbo’ who half of all Britain’s XL Bully dogs can be traced back to claims they only become dangerous when people inject them with steroids

The breeder of the dog who half of all Britain’s XL Bullys can be traced back to claims they only become dangerous when people inject them with steroids.

Dubbed ‘Killer Kimbo’, the US dog is thought to have hundreds of puppies –  while its own parents were reportedly a brother-sister pairing. According to BullyWatch this deliberately gave them a larger, more muscular frame.

But Gustavo Castro has sensationally claimed his pup was a ‘gentle giant’ who allowed the breeder’s six daughters to kiss and cuddle them. 

He has spoken out to say Kimbo – who is related to 32 of the 50 breeding stud dogs in the UK – is not necessarily to blame if he has aggressive offspring. Castro claims it is rather the fault of owners injecting their pups with steroids.

It comes amid a spate of attacks in recent weeks that has prompted the breed to be banned, including schoolgirl Ana Paun, 11, who was bitten while walking on her way to the shops and father-of-two Ian Price, 52, who was mauled to death last week. 

Half of all of Britain’s XL Bully dogs could ‘descend from one inbred animal from the US named Killer Kimbo’ (pictured)

Renowned ‘Killer Kimbo’, who is thought to have bred hundreds of puppies, is the product of two dogs from the same parents. [Stock Image]

Genealogy research revealed decades of inbreeding has created a shallow gene pool of unstable fighting beasts which are responsible for 70 per cent of dog attacks in Britain, according to The Telegraph.

Castro – who is based in the Huntington Park neighbourhood of Los Angeles – claims Kimbo now has as many as 600 offspring across the world.

‘Some people when they get my dogs they start injecting them with steroids and other stuff that they’re not supposed to, to get them big,’ he told The Sun.

‘All that stuff has side effects. You’re not going to get a normal dog, the dog’s going to be different. 

‘My dogs are naturally big. Puppies take more from the mother’s genes anyway. If the mothers are aggressive it isn’t necessarily Kimbo’s fault.’ 

Kimbo is renowned for its size and strength in the XL Bully community, and is responsible for half of British ‘stud’ dogs currently on the market. 

Castro now owns a Kimbo grandson and great-grandson – and claims he has not had any problems with either of them. He is pictured holding and playing with the beast on his social media.

Campaign group BullyWatch say products of Kimbo are responsible for at least ten violent incidents across the globe – the real amount is impossible to trace.

Scientist and campaigner for BullyWatch, Gloria Zsigmond, said: ‘Kimbo’s offspring became very, very popular and they’re still so popular in the UK to this day,’ she added that it was ‘extremely troubling’.

Following hundreds of hours of research using family trees uploaded by breeders, Ms Zsigmond found that 32 of the 50 breeding dogs were related to Kimbo.

Rishi Sunak vowed to bring in rules by the end of the year under the Dangerous Dogs Act to ban XL Bullys 24 hours after father-of-two Ian Price, 52, was mauled to death in a frenzied attack by two suspected bullies.

Ana Paun was walking to the shops with her 18-year-old sister when the powerful breed of bulldog leapt up at her from a bus shelter

She said: ‘A lot of the time, the Bully breeders are trying to hide how inbred the dogs are.’

‘Kimbo bled into all those bloodlines because he was early on and he was so dominant in breeding. There are some good bloodlines where Kimbo isn’t there, but there are many where he is,’ she told The Telegraph.

Andre Smith, owner of the Los Angeles-based Big Gemini Kennels, said that Kimbo’s owner should have stopped breeding the dog once the first attacks were reported.

The XL Bully breed has become one of the most fashionable in the UK with puppies selling for more than £2,500 – often sold to families who are told that they are placid and safe around children.

On Friday, the Prime Minister branded XL bully dogs a ‘danger to our communities’ and vowed to bring in rules by the end of the year under the Dangerous Dogs Act to ban them. 

It came after a horrific incident 24 hours earlier when father-of-two Ian Price, 52, was mauled to death in a frenzied attack by two suspected bullies.

Days before, Ana Paun, 11, was hurt by an American bully – a type linked to ten deaths since 2021.

Environment Secretary Therese Coffey is to convene a meeting with experts to define the XL breed, which is said to have originated in the US in the 1980s when American pitbull terriers were crossed with Staffordshire terriers.

Mr Price was killed by the two dogs which jumped out of a neighbour’s window yards from a primary school on Thursday afternoon. He reportedly died defending his elderly mother from the animals.

Father-of-two Ian Price (pictured), from Stonnall, Staffordshire, was killed by the two dogs which jumped out of a neighbour’s window yards from a primary school on Thursday afternoon. He reportedly died defending his elderly mother from the animals

The 30-year-old dog owner was arrested on suspicion of manslaughter and quizzed following Thursday’s horror attack. He has since been released on conditional bail (the dogs believed to have killed Ian Price pictured above)

An armed police officer carrying a rifle is seen patrolling the cordon in Stonnall where Mr Price was brutally killed by the two animals

Officers had previously said they were ‘aware’ of prior police interactions with the owner of the killer dogs after they were reported to be off the leash on one occasion, and mounted a dog on another.

Witnesses said the dogs entered Mr Price’s mother’s garden through a hedge before ‘setting’ on him in an attack said to have lasted up to 20 minutes.

The dogs bit Mr Price and ripped the clothes from his body leaving him dying in a pool of blood in his boxer shorts in Thursday afternoon’s horror attack just feet from his home.

The Stonnall incident saw air ambulance, paramedics and police officers, including armed response units, called to Main Street in the village shortly before 3.15pm. Despite the best efforts of medics on the way to hospital Mr Price, 52, was later pronounced dead.

Following Mr Price’s devastating death the owner of the XL Bully’s was arrested on suspicion of being in charge of dogs dangerously out of control and more latterly on suspicion of murder.

It came just days after brave schoolgirl Ana Paun spoke exclusively to MailOnline about the moment she was savaged by a dangerous Bully XL dog.

The 11-year-old told how the powerful breed of bulldog ‘which was suffering from heat exhaustion’ leapt up at her after lying unleashed in a Birmingham bus shelter as she walked home from buying sweets with her sister.

Traumatised Ana said: ‘The dog just came at me out of nowhere. I was walking to the shop with my elder sister and the dog was with its owner, who was standing by a bus shelter.

Ana remained in hospital for a day and was allowed home to recover last night with a bandaged arm

Ana’s mother has said she does not want the dog to be destroyed and has blamed the animals owner for the incident 

‘The dog stared at me and as I got closer it suddenly jumped up and bit my arm, it didn’t take its gaze off me and continued staring while it was biting.

‘It sort of locked on to my arm and wouldn’t let go. I was screaming as loud as I could.

‘The dog knocked me to the floor and was still attacking me. A man helped me and hit the dog which released it from my arm but it then lunged at me again and bit my shoulder.

‘I was in shock but another man managed to grab the dog from behind and pull it off me. The dog then chased someone else into the petrol station and attacked him on the forecourt.

‘I managed to get off the floor at this point and with my sister I ran into the shop to safety. There was a lot of blood pouring from my arm. The staff called the police and the ambulance and I was taken to Heartlands Hospital.’

She added: ‘I thought it was going to attack my face and neck and that I was going to die.

‘I kept screaming and screaming – I was petrified.’