Nigel Stepney has appeared in a court in Italy to answer questions over his involvement in last season's spy row.
McLaren were caught with technical data belonging to Ferrari, who have taken legal action despite F1's governing body drawing a line under the matter.
Stepney, the former head of development at Ferrari, is believed to have passed a 780-page technical document to former McLaren chief designer Mike Coughlan.
His laywer denied any secret technical information had been passed on.
Sonia Bartolini, representing Stepney, did acknowledge, however, that her client had contact with Coughlan.
Following three hours of questioning at a Modena courtroom in Italy, prosecutor Giuseppe Tibis said Stepney was "co-operative and thorough".
McLaren boss Ron Dennis, chief executive Martin Whitmarsh, chief designer Coughlan and engineering director Paddy Lowe have all been summoned to appear before the Modena court in the coming weeks.
McLaren were fined £50m and stripped of all their constructors' point for the 2007 season by the sport's governing body the FIA for their involvement in the spy row.
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