The attack has emerged just weeks after another of the killer's dogs was shot dead by police as it terrorised a neighbourhood.
Muneer Ahmed, who was locked up for 22 weeks for the killing, was found by police officers standing over the dog's body in an alleyway.
The 33-year-old was ordered to serve an extra 14 days to run concurrently after he threatened to empty a jug of water over the prosecution solicitor in an expletive-ridden volley of abuse.
Ahmed, of Priory Close, Smethwick, told the RSPCA that the dog had been struck by a car three days before. He decided to put it down himself because 'it was annoying him' and he knew vets would not help as it was a banned pitbull breed.
A month ago, Ahmed admitted letting two other suspected pitbulls run loose in Richmond Road, Bearwood – one of which had to be shot dead by police and the other recovered by the dangerous dogs unit. He pleaded guilty to being the owner of a dog which was dangerously out of control and will be sentenced on April 7.
For the killing of his dog he was sentenced to 22 weeks in jail and banned from owning, keeping, transporting or looking after dogs for life after admitting causing unnecessary suffering to the dog.
A court hearing heard that Ahmed had been discovered by police officers bending down in an alleyway off Barrett Street, Smethwick, next to the badly-beaten body of a dog with a brick nearby last April.
Ahmed told officers: "I killed the dog. I know it's dangerous and banned."
The court heard that during an interview with RSPCA officers, Ahmed had told them that the dog was annoying them. A post-mortem revealed the dog had a severely fractured skull. It also had injuries including broken ribs and a damaged liver.
"The scene was so bad one police officer described how the incident made him feel sick", said Mrs Gaynor Sutton, prosecuting for the RSPCA at Sandwell magistrates court. "This man is definitely a danger to dogs now and in the foreseeable future."
Mr Harmail Gill, defending, said Ahmed killed his dog as an act of compassion after it was hit by a car and was extremely remorseful for his actions.
Ahmed was found guilty of contempt after, while the bench was deliberating, he abused Mrs Sutton and a court usher.