Twenty years after Janet Brown was killed in her home, the Bucks Free Press reviews the facts from the case.

Cold case:

Mrs Brown, 51, was murdered at her home in Sprigs Holly Lane, Radnage, on April 10, 1995.

She was alone and is believed to have been attacked at some time between 8pm (her last telephone conversation) and 10pm (when a burglar alarm could be heard).

She was discovered the next morning by builder Nick Marshall and his 15-year-old son Ben.

Mrs Brown had been struck to the head a number of times with what police described as a heavy implement, possibly a metal bar.

The murder weapon has never been found.

She had also been gagged with packing tape and had her hands handcuffed behind her back.

These items were not believed to be on the property beforehand, and it is suspected that the killer brought them to the property.

She was left naked at the bottom of the stairs. There has never been a reason to suspect a sexual assault.

At the time of the crime, police thought it was possible that Mrs Brown had disturbed a burglary, and police are refusing to rule out this as a possible motive.

Windows had been smashed which strengthens this theory, they said.

A post-mortem revealed Mrs Brown had died of severe head injuries.

Over the course of the investigation more than 2,000 people gave statements to the police.

A campaign for information was started in the Bucks Free Press and Crimewatch also aired a video appeal.

2015 update: police investigate new DNA evidence and offer a £20,000 reward for information about killer.