Former Ferrari employee Nigel Stepney has turned the legal spotlight on the Italian team after he was forced to flee the country earlier this month.
Stepney insists he has been made a scapegoat
Stepney, formerly head of performance development, was sacked after being accused of leaking secrets to McLaren.
But lawyers are investigating whether Ferrari were involved in the high-speed car chases that dogged the Briton.
Ferrari could be the subject of criminal proceedings if evidence suggests they have been spying on him.
Stepney told the Observer newspaper that he had been followed by more than one car, with Italian plates, and when he cornered one of them, the men inside refused to speak to him.
His lawyer Sonia Bartolini told Italian newspaper La Repubblica: "At the right time we'll draw our conclusions. At the moment we're trying to trace the car plates to the subjects that followed Stepney, and then we'll file a complaint.
"Obviously, if it is confirmed that Ferrari are behind this, it would be very serious. It's one thing to keep an employee under control at the workplace, but it's quite another to spy on him at his home and to follow him at night.
No Ferrari materials or data are or have ever been in the possession of any McLaren employee other than the individual sued by Ferrari
"If that was the case, the Maranello [Ferrari] people will be called to answer for it in court."
Ferrari's legal representatives have launched an investigation into alleged espionage and sabotage involving Stepney and McLaren chief designer Mike Coughlan.
McLaren have been summoned by the FIA, Formula One's governing body, to an extraordinary meeting of the World Motor Sport Council to explain how Coughlan came to be in possession of a 780-page document relating to Ferrari's 2007 car.
An FIA spokesman would not comment when asked by the BBC to confirm a report in La Repubblica that Coughlan had shown the documents to several colleagues at McLaren.
The newspaper quoted from what it claimed to be the affidavit Coughlan had submitted to Ferrari as part of legal proceedings brought by the team against him in the UK.
According to the newspaper, Coughlan said in the affidavit that all the colleagues he showed the documents distanced themselves from them and advised him to destroy them.
McLaren released a statement on Monday saying an internal invesitgation had revealed "no Ferrari materials or data are or have ever been in the possession of any McLaren employee other than the individual sued by Ferrari [Coughlan].
"The fact that he held at his home unsolicited materials from Ferrari was not known to any other member of the team prior to the 3 July 2007".
The team reiterated that "no Ferrari information has at any stage been used to develop its car".
La Repubblica said Coughlan had not confirmed that his source for the documents was Stepney, who has denied supplying them. The report said Coughlan had only said he had received them via a courier service.
McLaren could be docked points or even disqualified from the world championship this year if they are found guilty under article 151c of F1's International Sporting Code.
This deals with "any fraudulent conduct, or any act prejudicial to the interests of any competition, or to the interests of motor sport generally".
Ferrari lawyer Massimiliano Maestretti told RAI television there was still some uncertainty over who knew about the documents and when some were delivered to Coughlan.
"The McLaren statement mentioned the documents were received at the end of April," he was quoted as saying, "but we have proof that there were more later than that with a May date."
McLaren's statement said they would "present the complete and accurate picture of events" at the World Motor Sport Council hearing.