Do not let Bill Blair down.

That is the advice of former deputy chief Kim Derry, who has been close friends with Toronto's chief of police for nearly four decades.

To Mr. Derry, then, the words that passed Chief Blair's lips on Halloween, after he acknowledged the existence of the video allegedly showing Mayor Rob Ford smoking crack cocaine, were piercing: "I'm disappointed."

Story continues below advertisement

This is a chief who, on the very day he was appointed in 2005, told The Globe and Mail of the importance of thwarting the sale and use of drugs. "Let me go on the record on this one," he added at the time. "I've never inhaled. I've never used any illicit drugs." Today, he is serving under a mayor who has smoked crack cocaine – while in office.

"He feels let down," Mr. Derry said. "You know how you depend on different people in your life? The mayor is to run the city, and to have a mayor who has disappointed you means that you have, now, the weight of the city on you."

It has been an extraordinary two weeks for Toronto, with allegations and evidence of questionable behaviour escalating by the day. It is an equally extraordinary moment for Chief Blair as he presides over a police force in a city embroiled in a crisis of leadership.

Chief Blair's announcement about the video came just hours after a 474-page police document revealed the mayor's meetings and communications with Alessandro Lisi, who faces drug and extortion charges. It is easy after the past week of Ford news to forget it was the chief's announcement, and his expression of disappointment, that set the stage for the war of words and the flood of questions that followed.

On the one hand, there is the mayor, his drug and alcohol use, a paralytic City Hall and the international headlines the scandal has produced. On the other, there is Chief Blair, a man with a roller-coaster tenure who is now being either heralded for the force's police work and acknowledging the existence of the video – Councillor Pam McConnell, who was chair of the police services board when the chief was appointed, said the revelation was in the public interest – or scrutinized.

Several questions have accompanied the probe. Why did police include as much as they did about the activities of the mayor, who has not been charged, in the affidavit regarding Mr. Lisi? Why did the video announcement come the same day the police document was released? Should the chief have announced he was in possession of the video? Given the sensitivities, should an outside force have been asked to help investigate?

Many have applauded the chief for putting a magnifying glass on the mayor. But Councillor Doug Ford, the mayor's brother, has condemned him for "politicking." Either way, the chief is a man with investigators who want to question the city's boss. And almost regardless of what happens next, his reputation – and legacy – will be coloured by how he manages this moment.

Story continues below advertisement

Chief Blair has faced fierce criticism before – after the G20 Summit, and after this summer's shooting death of Toronto teen Sammy Yatim – but nothing quite like this.

"Every 'i' has been dotted and every 't' has been crossed," said the chief's spokesman, Mark Pugash, about the investigation and how it was handled. "We've been accused of both targeting and shielding the mayor, which leads me to believe that we're probably going right down the middle, which is where we need to be."

The chief's every move is vulnerable to criticism – even a two-year-old fishing trip with a Toronto Police Services Board member was thrust to the fore by Councillor Ford, who said Andrew Pringle was in a conflict for vacationing with Chief Blair. On Thursday, at their monthly board meeting, members rejected the chief's request for more tasers.

Councillor Michael Thompson, who serves as vice-chair of the police board and has sparred publicly with the chief on budget issues, said he does not see any basis in Councillor Ford's accusations against the chief. "Irrespective of what the chief did or didn't do, he'd be damned if he did and damned if he didn't, quite frankly," he said.

Senator Vern White, a former chief of police in Ottawa and Durham Region, said deciding whether to ask another police force to investigate a case involving a politician is "always a decision chiefs wrestle with." He added that the tension between the mayor and the police is of concern.

"I would hope they get past that, for the sake of the city of Toronto," he said.

Story continues below advertisement

For Mr. Derry, the fact that "baby face" Bill had risen to the post of chief comes as no surprise. The two joked decades ago (although with an underlying confidence) that some day they would run the shop. And they did, rising through the ranks as the force swapped typewriters for computers, had its first black deputy chief, fought budget battles, faced controversy over the force's tactics in dealing with the mentally ill and confronted calls for the chief's head after the G20. Mr. Derry said that when Chief Blair was appointed in 2005, after losing his bid for promotion in 2000 in favour of Julian Fantino, he told the chief, "We're here."

The rise was not entirely surprising to Mike McCormack, head of the Toronto Police Association, either. He knew Chief Blair from their time together at 51 Division, a scandal-plagued police outpost located next to the crime-ridden Regent Park housing complex where relations between police and the community were at a nadir. It is also where Chief Blair, a fan of Jane Jacobs's work on the importance of the neighbourhood in crime reduction, confronted racism in the force and cut his teeth in community policing.

"He had credibility because he had walked a mile in our shoes," said Mr. McCormack, whose father was chief from 1989 to 1995. "He was definitely earmarked for promotion … I don't think he ever made any bones about being ambitious."

Chief Blair left 51 Division for the drug squad, where he wore his hair long to his shoulders as an undercover officer and was involved in some of the city's most high-profile drug busts. He later returned to 51 Division, where as superintendent, he took on the force's crumbling police cars, Mr. Derry said. When a bumper fell off one of the cars, he said the chief called a tow truck and had the car delivered to headquarters, making a point of what the force was up against.

Born in 1954, Chief Blair first attended the University of Toronto to study economics, with his eye initially on a law degree. But partway through the program, Mr. Derry said the chief changed course, thinking, "'You know what? I really want to be a police officer.'" (The chief later completed his U of T arts degree, with dual disciplines in economics and criminology.)

The two met at police college in 1976 in Aylmer, Ont. Because of their similar stature – Mr. Derry at six-foot-four and Chief Blair at six-foot-five – they were oftentimes paired for use-of-force exercises and marched in formation side-by-side. By chance, they were then posted to 51 Division, where they formed a foot patrol (in part because Mr. Derry said they were too tall for the police cars of the day).

Story continues below advertisement

They became known as The Pair Who Walked The Park. And when they were encircled by at least six "gang bangers" trying to stop them from arresting one of their own, they "came together," Mr. Derry said. In the melee, Mr. Derry threw a punch that accidentally landed on his partner's jowl, dislocating Chief Blair's jaw. After the fight broke up with the whirring siren of an approaching police car, the two marched the accused in on foot, dislodged jaw and all.

"It was one of those defining moments where the bad guys respected us because when we said we were going to do something, we did," Mr. Derry said.

Behind the desk in the chief's office is a framed image, a gift from staff and something he enjoys showing to visitors dropping into his large office inside Toronto Police headquarters. The photo is a composite image of Chief Blair side-by-side with his late father, who was also a veteran Toronto police officer, standing next to Queen Elizabeth II.

"His dad [John Blair] was very regimented," Mr. Derry said of the chief's upbringing. "He ran the place like, 'Yes, sir, no, sir' … He had a hard side and a soft side … Bill is a little softer."

The chief married his wife, Susanne, 36 years ago after meeting at Fairview Mall, where Chief Blair had been a security officer, Mr. Derry said, adding that the two men and their wives launched an embroidery business in Durham, Ont., in the 1980s. He said the chief is protective of his wife, daughter and two sons, doing his utmost to shield them from any controversies that swirls around him.

The most high-profile of the controversies, of course, was over the policing tactics used during the G20 Summit in 2010. Scathing probes ensued, there were demands for the chief's resignation and calls for a judicial inquiry into what activists described as a "police and political abuses."

Story continues below advertisement

"It was difficult," said Mr. Derry, who retired as deputy chief in 2011, and now heads security company Executek. "We had 10,000 officers and we had probably 20 that went rogue on us … That was disappointing – that day, we both said that. He was disappointed."

That was the summer of 2010. In a sit-down interview two months ago, the chief said the most difficult event of summer 2013 was the July shooting death of Mr. Yatim, an 18-year-old who was alone on a streetcar wielding a knife when he was he shot multiple times and then tasered. Constable James Forcillo was charged with second-degree murder in the shooting that was captured on video.

"I certainly was concerned with what I was viewing on that video and I took certain actions in the immediate aftermath to address some of those concerns," he said, adding that he didn't take any time off this summer. "I think video provides us with the best evidence of what transpired, and that video is very helpful both in conducting investigations, but also learning lessons."

Now, videos of a very different kind – the one of the mayor allegedly smoking crack, and the one that surfaced Thursday showing him in a drunken rage – has taken over the headlines, and the court process continues to unfold.

Friday was the deadline for written submissions from lawyers seeking the release of some redacted portions in the 474-page police document. Justice Ian Nordheimer could make his decision early next week, setting the stage for the release of information that could potentially reveal more about the mayor's connection to Mr. Lisi and Project Traveller, a year-long drugs and guns operation that culminated in multiple arrests in June. Also, on Tuesday, Justice Nordheimer ruled that the law does not prevent the court from releasing wiretap information contained in a 119-page document police used to secure Project Traveller. His ruling could open the door to the public learning more about the case.

One thing, though, is known right now: "Once you disappoint [the chief]," Mr. Derry said, "it's very hard to gain that trust back."

Story continues below advertisement

With reports from Patrick White, Joe Friesen and Ann Hui, and Kim Mackrael in Ottawa.