The man charged with killing a 10-year-old girl in Toronto pleaded guilty to first-degree murder on Thursday.

Michael Briere, 36, who was charged with the murder of Holly Jones last year, showed no emotion as he loudly said "Guilty" when asked in court how he pleaded.

Holly disappeared just steps from her west-end Toronto home on May 12, 2003. Her dismembered body was found a day later.

Briere, a software programmer who lived a few blocks from Holly's home, was arrested on June 20, 2003.

A first-degree murder conviction carries an automatic sentence of life with no chance of parole for 25 years.

A guilty plea in this type of case is considered extremely rare.

A statement of facts filed with the court gave previously unreleased details about Holly's killing.

It confirmed that the girl was sexually assaulted before she was murdered, and revealed that she was strangled to death within an hour of her abduction.

Briere then dismembered Holly, putting her body parts in two gym bags before dumping them in Lake Ontario.

There had been rumours that Briere would plead guilty after he waived his right to a preliminary hearing in the case. Briere's lawyer had said his client wanted to spare Holly's family the pain of hearing detailed evidence in the girl's murder.