Phil Mackereth, who joined Renault in September 2006, brought engineering drawings and technical spreadsheets from McLaren that were added into Renault's database.
The information included drawings of the four basic systems as used by McLaren: the internal layout of the fuel tank, the basic layout of the gear clusters, a tuned mass damper and a suspension damper.
"This information was loaded at the request of Mr. Mackereth onto his personal directory," Renault said Friday in a statement. "This was done without the knowledge of anyone in authority in the team.
"Our formal investigation showed that early in his employment with Renault, Mr. Mackereth made some of our engineers aware of parts of this information."
Renault said it suspended Mackereth on Sept. 6 when officials learned of the leak, and that it alerted McLaren and FIA - motor sport's governing body - even though none of the information had been used.
"Witness statements from the engineers involved have categorically stated that having been briefly shown these drawings, none of this information was used to influence design decisions relating to the Renault car," the statement said.
On Thursday, FIA summoned Renault officials to a Dec. 6 hearing of the World Motor Sport Council to answer a charge of having "unauthorized possession of documents and confidential information" of McLaren cars between September 2006 and October 2007.
Renault's summons adds an additional twist to a spy scandal involving McLaren that overshadowed much of the last F1 season.
McLaren was fined a record US$100 million by the World Motor Sport Council on Sept. 13 after FIA found the team guilty of using leaked secret data from Ferrari.