Russell Williams is escorted from the Belleville Superior Court under heavy armed guard and in handcuffs after pleading guilty to murder Monday. Photograph by: Julie Oliver , Ottawa Citizen

BELLEVILLE, Ont. — The depth of Russell Williams' shocking sexual depravity was on full view Monday.

Crown prosecutors said that for 2 1/2 years from the fall of 2007, Williams led a secret life that saw him steal hundreds of pieces of underwear from the bedrooms of girls as young as 12 during break-ins throughout the Ottawa suburb of Orleans and Tweed, Ont., where he and his wife had homes.

Williams will be sentenced later this week to life imprisonment with no possibility of parole for at least 25 years.

He pleaded guilty in court here Monday of two counts of murder, two of forcible confinement and sexual assault, and 82 counts of break and enter.

The 47-year-old commander of Canadian Forces Base Trenton, Canada's largest air force base, murdered Jessica Lloyd, 27, of Belleville, in January this year and Cpl. Marie-France Comeau, 37, a flight attendant under his command, in November last year.

Circumstances surrounding the murders will be dealt with later in the week.

Crown lawyers said the respected, high-achieving air force colonel embarked on a journey of escalating predatory sexual behaviour that began on Sept. 9, 2007, when he stole underwear from the bedroom of a 12-year-old neighbour near his home in Tweed, 40 kilometres north of CFB Trenton.

Later, in one of the thousands of sexually explicit photographs Williams took to meticulously catalogue his crimes, he photographed himself with the pants of his military uniform at his knees, exposing a pair of pink panties.

The majority of the pictures presented in evidence Monday were far more explicit.

During almost every break-in, he photographed himself cavorting around women's bedrooms wearing only bras and panties. In one image he is seen with panties wrapped around his face.

Many of the self-portraits featured him with underwear hanging from his erect penis or lying naked on the beds of his victims masturbating into underwear.

He took other pictures of himself at home.

In almost every case, he photographed an open underwear drawer and himself in various poses with the underwear.

The images, stored on his computer along with records of all his crimes, were found in Williams' Ottawa home shortly after he was arrested in February following a roadside check by police looking to match specific tire treads found at the scene of Jessica Lloyd's home.

Williams told police that he broke into homes of good looking girls and women when he knew the houses to be empty, but preferred women in their late teens to early 30s. Despite his claim, in 18 of his break-ins women under 18 — some as young as 12 — were the residents targeted.

He stole underwear from 25 homes near the home he shared in Orleans with his wife Mary Elizabeth Harriman and from 23 homes in the area of their second home in Tweed where Williams usually lived alone during weekdays. He broke into some of the homes several times but of his 48 victims, only 17 reported break-ins to police before he was arrested. Several didn't know their homes had been broken into until after Williams' confession.