The public should "not approach" an absconder from Kirkham Prison, police said.
Paul Creedy, 26, was sentenced to ten years in prison for manslaughter and conspiracy to commit robbery in 2013.
Creedy, formerly of Mayfair Road, Wythenshawe, absconded from Kirkham's open prison yesterday.
The force said Creedy has links to Greater Manchester, and is described as being 5'6". having blue eyes, a thin build, black hair, and a scar on his forehead.
He was originally jailed after the death of a man who was left to drown after Creedy and his fellow gang members pushed him into a canal during a crime spree.
Police told the public not to approach him, and to call 101 if they have any information, quoting log reference 1338 of August 14.