F1: Jenson Button's form a cause for concern
It is one of the biggest mysteries of the season, enough to tax the mind of many a great detective, but the question being asked by many is: what has happened to the form of Jenson Button?
The result in Malaysia aside, when Button inadvertently slid into Narain Karthikeyan's HRT on a damp circuit and wound up 14th, the 32-year-old's performances over the first three races suggested a title tilt was on the cards.
At that stage, after winning in Australia and finishing second in China, Button was second in the championship to McLaren team-mate Lewis Hamilton by just two points.
Since then Button's world has come crashing down around him, with just two further points collected in the subsequent four races to leave him 43 adrift of current leader Hamilton.
Button has insisted it is nothing to do with the Pirelli tyres, the Italian manufacturer having turned Formula One on its head this year with its range of rubber that saw Hamilton extend the record for different winners to start the season to seven in Canada on Sunday.
That point was proven in Montreal as Button found himself one and a half seconds per lap slower than Hamilton, as well as Ferrari's Fernando Alonso and reigning champion Sebastian Vettel in his Red Bull.
Given Button's prior renown for coaxing the best out of any set of tyres, he knows full well he is not one and a half seconds off the pace of any of his rivals, and in a car that is one of the best in the field this season.
You ask Button as to the problem and he simply has no clue, and that is not him trying to be evasive and shy away from his issues because the Briton is one of the most honest, forthright people you could wish to meet.
It resulted in Button admitting to being "lost and very confused" in the wake of his 16th-place finish at Montreal's Circuit Gilles Villeneuve.
At least he has not lost his sense of humour.
Departing the scene of another awful result, a broad grin creased his face as he said: "Things might be bad at the moment, but look who I get to go home with!" pointing to model girlfriend Jessica Michibata.
It was gallows humour in an attempt to mask his difficulties because these are worrying times for a man who has not endured such a wretched run since his miserable days at Honda in 2008.
One suggestion is that Button is incredibly sensitive to change, that a car anything other than perfectly set up to his liking and he struggles to get the best out of it.
Other drivers, Hamilton among them it has to be said, can still wrestle with a car even when they find it a struggle to handle.
It has to be remembered exhaust blown diffusers were banned from this season, the device apparently giving Button the balance he likes at the rear.
At the start of the season McLaren's initial solution suited his way of driving, but as the year has progressed and the car developed, so he has lost his way.
Of course, suggesting Button revert back to the car he drove to victory in Australia is impossible because - for all intents and purposes - it is slower than the one he drove in Canada, even though it does not appear to be the case bearing in mind how rapidly he has gone backwards.
Instead, it is down to McLaren's engineers to find a solution, which is why there was so much dismay at the amount of running lost in Friday practice in Montreal.
One oil leak resulted in two gearbox changes and precious little time to evaluate a new rear suspension it had been hoped would provide a way forward.
Instead, Button suffered such abysmal degradation to the rear tyres he ran out of new sets in qualifying, which in turn compromised his race.
There is hope McLaren are heading down the right road and that they will have cracked the problem come next weekend's European Grand Prix in Valencia, or certainly the British at Silverstone a fortnight later.
If not, with time ticking on and races flashing by, Button could find himself a long way adrift and effectively out of the title running come the conclusion to his home race.