A youth who set his pit bull terrier on a 16-year-old boy before stabbing him to death has been sentenced to life in prison.

Crisdian Johnson, will serve a minimum of 24 years behind bars after an Old Bailey Jury found him guilty of the murder of Oluwaseyi 'Seyi' Ogunyemi and the attempted murder of a 17-year-old boy who was also attacked by dogs and stabbed nine times during the same attack.

Crisdian Johnson's brother, Shane Johnson, 20 who also stood trial for murder, attempted murder and GBH with intent was unanimously found not guilty on all counts.

Crisdian was believed to be a member of a Lambeth based gang and this incident is believed to have arisen out of escalating violence between him and a rival gang.

The Judge today was there was “no explanation” for the animosity between the two only that they were from different gangs.

“Wild animals”

Police were called to Larkhall Park, Wandsworth in April of last year, to reports of a large number of males stabbed.

Seyi, who suffered from Crohn's Disease and was very slightly built, had 6 stab wounds to the abdomen, the fatal stab wound entered via the right armpit and nicked the aorta causing catastrophic bleeding. He also had dog bites on his right calf, thigh and shoulder.

Witnesses to the murder described seeing a group of males with two dogs surround Seyi and his 17-year-old friend and attacking them like 'a pack of wild animals'.

Both victims were also attacked by the dogs, a large light brown pitbull / mastiff cross (Tyson) and a smaller brown Staffordshire Bull Terrier/ pitbull cross (Mia), having been ordered to do so.

Seyi received 6 stab wounds and his friend received 9 stab wounds but fortunately the friend survived the attack. An area search for the suspects immediately took place and 13 minutes after the attack two Lambeth officers saw a bare-chested man, Crisdian Johnson, covered in blood walking along Wandsworth Road.

Trapped by Dog DNA

Being aware of the recent incident the officers arrested him on suspicion of murder and made all efforts to preserve any forensic material by treating him as a crime scene. This good practice enabled detectives to identify DNA found on his body and clothing as matching Seyi as well as Tyson.

A few hours after the attack Shane Johnson presented himself at Kings College Hospital with a stab wound and was subsequently arrested.

Tyson received two stab wounds during the attack and was taken to a Blue Cross animal hospital for treatment. Subsequent enquiries revealed that he was owned by Crisdian Johnson and had been chipped and tagged with a serial number.

A blood trail was found leading from the murder scene to Sheldon Court which forensic analysis showed to be from a dog. Tyson had received two stab wounds during the attack and the trail of his blood was matched to him by Gen Probe Dog DNA Specialists.

This groundbreaking forensic work matched the blood from the trail to Tyson's DNA to a match of one in one billion. Police recovered the other dog, Mia, after a search warrant was executed at an address in Sheldon Court SW8 on 27 July 2009.

Both dogs were seized and taken into police custody by the MPS specialist dogs unit.

Speaking after the verdict DI Mick Norman (Homicide and Serious Crime Command) said:

"This horrific attack was committed on a very slight teenage boy who stood no chance of defending himself. The fact that Crisdian Johnson also ordered dogs to take part in the attack illustrates his sickening attitude to violence.

The advances in Dog DNA and forensic work now means that anyone who owns a dog and uses it to attack people can be identified and prosecuted."