A prisoner has died after being stabbed in the chest by a fellow inmate at a privately-run jail.
Mr Reid was stabbed in a living unit at HMP Rye Hill
Wayne Martin Reid, 44, from Balsall Heath, Birmingham, was stabbed at the Rye Hill Prison near Rugby, Warwickshire, at around 1630 BST.
He was given first aid by officers and medical staff immediately following the incident, but was pronounced dead at 1700 BST on Wednesday.
The dead man was serving seven years for robbery.
John Bates, a spokesman for prison operators GSL, who run Rye Hill jail, said a police investigation was now under way.
He said the assault on Wayne Reid took place in a living unit at the jail.
"He sustained a stab injury to the chest and he was later pronounced dead," Mr Bates said. "First aid was immediately given by prison staff and medical staff.
"Our condolences have been passed to the family and friends of Mr Reid.
Mr Bates was unable to confirm the type of weapon used and how many assailants had taken part in the assault.
Rye Hill jail, which opened in 2001, is a Category B jail and holds around 660 prisoners.
The prison has come under the spotlight over the past month following several incidents.
Last month, a prisoner was found hanged in his cell in the segregation unit, where he had been placed following concerns about his behaviour towards staff and other inmates.
Michael Bailey, 23, from Birmingham, had been serving a four-year sentence for supplying drugs.
Two members of staff were suspended following the incident because of alleged irregularities with documentation, not as a direct result of Mr Bailey's death.
Last week, a prisoner on suicide watch at Rye Hill failed in a High Court bid for the right to be given razors, so he could self-harm to relieve the stresses that could lead to him killing himself.
A judge ruled that the suggestion that inmate Jeffrey Watkins should be provided with the means to self-harm "flies in the face of what we regard as civilised standards".