Warning: This story contains details that may be disturbing to some readers.

A court heard chilling details Monday of Col. Russell Williams's double life, including the thousands of graphic photos he took of himself wearing stolen women's underwear, and the sexual assault of a young mother as her baby slept nearby.

The proceedings began Monday morning in a Belleville, Ont., courtroom where Williams, former commander of CFB Trenton, pleaded guilty to two murders, two sexual assaults and 82 break-ins in Eastern Ontario.

The 47-year-old admitted to murdering Jessica Lloyd, whose body was found in February in a field near her Tweed home, and Cpl. Marie-France Comeau, who served as a flight attendant on military flights that Williams piloted. Comeau was found dead in her home last November.

In the final charge to be addressed in court before the session ended for the day, the Crown described details of the sexual assault of a young mother, whose identity is protected by a publication ban.

The victim woke up in her bed to Williams holding her head down before being tied up and blindfolded and photographed in various states of undress. The attack lasted for about two hours.

The court heard the victim told police that Williams treated her more nicely after she told him he didn't seem like the type of person to commit such acts. The victim also told police Williams ‘seemed like a dad.'

Before Williams left, he told the young woman to count to 300 before untying herself. She stopped at 70 and Williams told her to keep going. When she reached 200 she realized he was gone and called police.

For hours on Monday, prosecutors described to a shocked courtroom how Williams took thousands of graphic photographs of himself wearing women's and girls' underwear during dozens of thefts.

The list of charges was so long that it took nearly 40 minutes to read through in court. The crimes began in the fall of 2007 and ended at the start of this year.

After Williams entered his guilty pleas, a Crown prosecutor read aloud an agreed statement of facts, which provided details on how the disgraced colonel selected his victims.

The prosecutor said Williams would stake out the homes of young, attractive women, before breaking in and stealing their lingerie and other items.

Generally the women he targeted were between their late teens and early 30s, though in a few cases Williams broke into homes where pre-teen girls lived. He broke into the bedrooms of at least 12 girls under the age of 18.

After breaking into a home, Williams would hunt for lingerie in bedrooms. Then he would model the underwear he intended to take and would masturbate.

He always took a photograph of the room where he found the underwear and generally a photo of himself wearing it, prosecutors said.

The prosecution also said Williams took thousands of these photos, including a shot of himself wearing underwear that belonged to twin 11-year-old girls.

The court was shown numerous examples of these photos, some of which showed Williams masturbating for the camera.

Williams would then take the underwear home, adding to a growing collection of stolen clothing.

Prosecutors say he kept a time and date stamp on all of the photos, which he stored on hard drives that he kept hidden in his basement ceiling.

At his home, Williams eventually burned some of the stolen items once he had collected too many to hold onto.

During the morning court session, Williams, wearing a dark suit, kept his head down as the photos of himself were shown in court.

In the afternoon, Williams looked up from time to time and stared at the graphic images.

Williams was a well-respected soldier and family man leading a double life until his arrest on Feb. 7. Three days before, Williams had driven through a police checkpoint, set up to compare car tires to tread marks found outside of Lloyd's house after she was murdered.

The tires on Williams' SUV matched those tread marks.

Victims terrorized

During one break-in, Williams took items from three female members, between the ages of 12 and 21, of an Ottawa family.

One daughter reported finding a photo album left open to a page in which she had filed an old photo ID. Another daughter found personal pictures laid out on her bedroom floor, while another found a Word document on her computer with the word ‘merci.'

At another break-in, a 15-year-old girl was too scared to sleep in her own bedroom after dozens of items were taken. At yet another, Williams stole dozens of items from a young woman and left her a lurid letter.

In July 2009, Williams' behaviour escalated, court heard. In one instance, he watched from the backyard as a woman undressed and got into the shower. Williams then undressed, entered the home, stole a pair of panties and left.

The court also heard that Williams saved screen shots of Ottawa police news releases about a string of break-ins and thefts.

In addition to the statement of facts, the court will hear victim impact statements over the next few days.

Lloyd's brother Andy said outside court he and his family look forward to giving their statements to "let (Williams) and the courts know, and the parole board in 25 years, how this has affected us."

Lloyd told reporters he was appalled at the photographic evidence presented by prosecutors.

"Everybody's probably going to think the same thing I thought," Lloyd said. "I thought it was disgusting. Some of the pictures I thought were terrible."

The courtroom was packed with family members of victims, journalists and curious members of the public, many of whom struggled to contain their emotions. Some had to leave the courtroom as the more graphic photographs were displayed.

Greg Bowerman, a civilian cook at CFB Trenton, said the case "defaces the Canadian government (and) our people.

"Somebody that high-ranking doing something like this, it's a sad day for Canada," Bowerman said.

Williams will be sentenced later this week. He faces an automatic sentence of life in prison for the murders he committed.

His shocking crimes have drawn the attention of media across Canada and even the U.S. On Monday, reporters from CBS News and the New York Times attended the hearing for the disgraced colonel.

Williams is also facing a $2.45-million civil lawsuit from one of the women he is accused of attacking. That case is separate from the criminal charges he pleaded guilty to on Monday.

Gen. Walt Natynczyk, Chief of the Defence Staff, issued a statement on Monday afternoon in reaction to Williams' guilty plea.

"The tragic events surrounding Colonel Russell Williams stunned all Canadians and none more so than the members of the Canadian Forces. Today's guilty plea is the first step in a healing process that will no doubt take many years," said Natynczyk.

"Upon formal conviction we will be in a position to officially begin the administrative process that will lead to Colonel Williams' release from the Canadian Forces. This will be completed as quickly as possible."

The proceedings will resume at 10 a.m. Tuesday.

With files from The Canadian Press