Peter Gilheney disappeared from HMP Standford Hill, in Eastchurch, on Monday. Kent Police said the 29-year-old, failed to return after a short release period.
Gilheney, is described as 5ft 2ins, with a stocky build. He is the fourth prisoner to escape from HMP Standford Hill this year.
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Tuesday afternoon's weather for the west of the region
Tuesday afternoon's weather for the east of the region
Police believe it is a "distinct possibility" that Halliwell was a serial killer, beyond the two murders he was convicted for.