A Broadmoor patient pleaded guilty today to killing two women in a seaside town 12 years ago.
The bodies of Clare Letchford, 40, and 75-year-old Beryl O'Connor, known as Dornie, were discovered strangled and burned in their flats less than 100 yards apart in Hastings, East Sussex, in January 1998.
Sussex Police's major crime branch announced in April last year that they were re-investigating the murders.
Today at Reading Crown Court, Graham Fisher, 36, of Broadmoor Hospital, Crowthorne, Berkshire, admitted two counts of manslaughter, police said.
Fisher had previously pleaded guilty to the attempted murder and attempted rape of a Czech student, now aged 30, on a Hastings to London Charing Cross train in the same month of the killings.
And he also admitted two counts of rape of a woman in her early 40s at a property in Bromley, south east London, in 1991.
Fisher was remanded in custody to face sentencing for all offences at Maidstone Crown Court, in Kent, on July 22.
Ms Letchford was found dead in her rented basement flat in Cornwallis Gardens, Hastings, where she lived alone, on January 18 1998, and Ms O'Connor was discovered at her home in nearby Clifton Court, Holmesdale Gardens, eight days later.
Their killer strangled them before setting their bodies on fire, using their clothes to fuel the flames.
A Home Office pathologist found that Ms Letchford was badly burned, with a pair of shoelaces tied around her neck and a cushion cover over her head. She died from smoke inhalation.
At an inquest into their deaths, East Sussex coroner Alan Craze recorded verdicts of unlawful killing and said they were vulnerable victims of "despicable and needless" crimes.
Police said last April that the investigation into the murders was complex and wide-ranging but the Crown Prosecution Service (CPS) would be passed details of their "significant progress" shortly.
Fisher was charged three months later.
The attack on the Czech student happened on January 26 that year when she was viciously attacked in a toilet just three months after arriving in East Sussex as an English language student.
The victim, who has since returned to her homeland, was found by a train guard, covered in blood and with severe head injuries, and is said to suffer still from the ordeal.
All three cases featured on the BBC's Crimewatch programme.