TORONTO (AP) — A military commander charged with several counts of murder and sexual assault in a case that shocked Canadians was to appear in court in person for the first time Thursday.

Col. Russell Williams — an elite pilot who once flew Queen Elizabeth II and other dignitaries around the country — was the commander of Canada’s largest Air Force base until he was charged earlier this year with the murder of two women, the sexual assault of two others and 82 break-ins, during which he stole women’s panties. He has previously taken part in court hearings by video link from a detention center.

Andy Lloyd, brother of one of the murder victims, Jessica Lloyd, said prosecutors told him Williams would likely plead guilty on Thursday but could still change his mind at the last minute.

“Nothing is set in stone until the words are actually said in court,” Lloyd said.

Messages left with Williams’ attorney were not returned.

The case has shocked the country, hurt soldiers’ morale and prompted fears that the commander of Canada’s most high-profile military base and the man who once flew Canadian prime ministers could have been a serial killer.

Williams waived his right to a preliminary hearing in August and was ordered to stand trial and return to court on Thursday. The 47-year-old is charged with the first-degree murder of Lloyd, 27, whose body was found in February, and Marie Comeau, a 38-year-old corporal under his command who was found dead in her home last November. Both women were asphyxiated.

He is also charged with forcible confinement, breaking and entering and sexual assault after two other women were attacked during separate home invasions in the Tweed, Ontario area in September 2009.

“It’s just bizarre. I’ve never seen anything like it,” said retired Lieutenant-General Angus Watt, who once promoted Williams. “It was a shock to everybody because he was a high ranking officer in a leadership position, but the more we learned about it the more you realize this is the act of a single depraved individual and he does not represent an institutional failure at all by the military.”

Williams worked under Watt as a staff officer in charge of transport aircraft when Watt was commander of the Air Force. Williams said he was hard working and capable.

“He impressed everybody with his leadership and staff skills. He was a high performing individual,” Watt said. “Everybody is baffled. I’ve talked to some of his closet friends who flew transport airplanes with him and they had no, absolute no hint, no idea whatsoever.”

Williams is now charged with breaking into 47 homes 82 times, beginning in 2007, including one home nine times. Most homes were burglarized repeatedly on the same street.

Angela McCanny, whose Ottawa home was broken into on back-to-back days in 2008, said that all the women’s underwear in the house was stolen.

Anne Marsan-Cook, whose Belleville home was broken into on consecutive days in 2009, said her sex toys and all her underwear were taken. She also said a chilling message was left on her computer: “Go ahead, call the police. I want to tell the judge about your really big dildos.”

“I was one of the lucky ones,” Marsan-Cook said.

The Ottawa Citizen cited police sources as saying police seized 500 women’s undergarments from Williams’ Ottawa home.

Court documents allege Williams broke into Comeau’s home days before he is accused of killing her. Another alleges that Williams twice returned to the home of one of his victims to steal items after he sexually assaulted her.

Most of the homes were in Ottawa, where Williams has a house with his wife, and in the Tweed, Ontario, area, where Williams lived while he worked at Canadian Forces Base Trenton in Trenton, Ontario.

“It’s crazy. I don’t know how he could be doing all this and make time for it and nobody be aware of it,” Andy Lloyd said. “He was a busy man, by the sounds of it, with 82 charges over so many months.”

Associated Press news researcher Rhonda Shafner in New York contributed to this report.