Officials in the Ontario government aren't explaining why former Conservative MP Rahim Jaffer seemingly got a slap on the wrist, but Premier Dalton McGuinty suggested the police may have made mistakes during the arrest.

"I'm not familiar with the particulars of the investigation, but I have confidence that the Crown made the right decision given the circumstances," McGuinty told reporters Wednesday.

"I also have confidence that the Crown would have, or should have, spoken with the police investigators to make sure they clearly understood the challenges associated with any methods they may have adopted."

However, OPP Commissioner Julian Fantino issued a news release Wednesday saying he supported his officers.

"I am confident that the OPP conducted a thorough and detailed investigation in this case and obtained the necessary grounds to lay the charges. Our officers acted in good faith, professionally and in the best interest of public and officer safety during all aspects of this investigation," he said.

Police pulled over Jaffer, husband of former cabinet minister and Simcoe-Grey MP Helena Guergis, in September 2009. As a result, they charged him with possession of cocaine, impaired driving and speeding.

After negotiations with Howard Rubel, Jaffer's lawyer, Jaffer pleaded guilty to a count of careless driving under the Highway Traffic Act. The court imposed a $500 fine and Jaffer made a $500 donation to charity.

"I'm sure you can recognize a break when you see one," Justice Doug Maund told Jaffer --- who lost his Edmonton, Alta. seat in the 2008 federal election -- when he heard the case on March 9.

One media report suggested that police conducted a strip search of Jaffer and didn't allow him to speak with his own lawyer after first getting advice from a legal aid lawyer, thus violating Jaffer's rights under the Charter of Rights and Freedoms.

The opposition parties called on the government to explain how serious charges ended up as a relatively light slap on the wrist.

"We want the attorney general to provide an explanation to Ontarians about how someone of such a high profile could get away scot-free, really, with the kind of criminal behaviour he was charged with," said NDP Leader Andrea Horwath.

"The government has to give us some explanation of what went wrong here. Why was this person able to walk away pretty much from a drunk driving charge and a drug possession charge?"

The Progressive Conservatives noted that charge reductions are part of the justice system, but agree that the Jaffer case should be explained.

"I know more about it from watching the (news) last night, and I think people do have an interest in having some light shone on what happened," said Opposition critic Norm Miller.

At the time of Jaffer's sentencing, Rubel had said his client had always "refuted" the allegations of drug possession or drunk driving, and that the outcome validated that stance.

The whole controversy has taken a toll on Guergis, who has also had her own problems in recent weeks -- and is now being represented by Rubel.

Prime Minister Stephen Harper announced Friday that he had accepted Guergis's resignation as minister of state for the status of women -- and announced that he had asked the RCMP and ethics commissioner to investigate.

However, Ethics Commissioner Mary Dawson said Monday that she's not in a position to proceed with an inquiry.

CTV News reported Tuesday night that Harper acted after hearing from a Conservative lawyer in Toronto that a private investigator had raised concerns about the potential threat of blackmail arising from allegations about the purchase and use of drugs.

However, it isn't clear who might have purchased or used the drugs, or who might have been the object of blackmail.

On Wednesday, Guergis told The Canadian Press that the story was "completely ridiculous and an example of rumours gone amuck." On Tuesday she told CTV via email that she wasn't in a position to respond fully, and that it was difficult to answer allegations that come from anonymous sources.

With files from The Canadian Press