A police manhunt for an escaped 52-year-old British killer ended Sunday after he voluntarily returned to a psychiatric hospital not far from the Swiss border.

John Herbert, who is originally from Fulham in London, was discovered missing from the hospital in Novillars, which is 10 kilometres north of Bescançon, early on Thursday, prompting an alert from police, French daily Le Parisien reported.

John Herbert (Screengrab/arpd.idf.org)

After he came back to the hospital on Sunday afternoon Herbert was first checked by doctors and then interviewed by French police. It wasn't clear why he ran off and investigators were still piecing together what he did will on the run.

Herbert's disappearance was first discovered during a head count by staff, when a worker noticed Herbert had tucked a guitar under his bed sheets to give the impression he was asleep in his bed.

He’d been declared mentally unfit for trial and forcibly committed to the hospital after beating his cellmate to death with a four-kilo weight while serving a six-month sentence in September 2011.

The man was behind bars because he’d failed to comply with the terms he’d been sentenced to after being convicted of raping his female partner in June 2010.