Lewis Hamilton's McLaren team were last night notified they are under investigation in the Ferrarigate inquiry.
Officers of the Modena court visited the team as the world championship leaders prepared for the Italian Grand Prix.
But former motor racing hero Jackie Stewart slammed the F1 governing body and said the inquiry was verging on a vendetta.
And the first casualty appeared to be world champion Fernando Alonso.
Sources close to the Spaniard said he might consider a year sabbatical if advanced talks over a switch to rivals Renault do not come off.
Stewart believes the best season's racing in years is being wrecked by machinations behind the scenes.
And with sponsors nervous over the effect on F1's reputation, he slammed the governing body for washing the sport's dirty linen in public.
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His comments come amid paddock unease that the fine line between a detailed investigation and a witch-hunt has been crossed.
McLaren are to appear before the world council on Thursday for the second time facing new evidence and the possibility of a two-year ban.
Stewart said: "It now looks like a vendetta and that is very serious. It is scandalous and the governing body have got a lot to answer for.
"They take an immense amount of money out of the sport and yet what do they bring to it?
"Right now they are bringing dirty linen.
"There is an enormous amount of damage being inflicted to the sport totally unnecessarily."
