A Canadian pig farmer accused of being the country's worst serial killer goes on trial later on Monday.

Robert Pickton has been charged with the murders of 27 women - most of them sex workers and drug addicts.

Mr Pickton was arrested four years ago when dozens of police swept onto his farm in the suburbs of Vancouver, and has been in custody since then.

Investigators spent months sifting the soil on the farm, conducting DNA tests to provide the evidence against him.

The police have been criticised for not taking the disappearances very seriously at first, but now there is no question that this is a major case, the BBC's Ian Gunn in Vancouver says.

Lengthy search

Since the arrest of Mr Pickton in 2002, the charges have slowly climbed to a gruesome 27 counts of first degree murder.

This followed a painstaking and lengthy search of the land and farm buildings, where the remains of 31 women have been found.

Most of the women he is accused of killing vanished over a period of 25 years.

The trial is set to begin at about 0900 (1730 GMT) in a small suburban courthouse.

However, a court ban prevents journalists from reporting any of the evidence until a jury has been chosen.

BBC News