Hans Wilhelm Gab, vice-president of GM Europe, said Mr Lopez continued to collect internal Opel material even after he was formally in the employ of Volkswagen.
The Hamburg state prosecutor's office also announced an investigation into suspected perjury by Mr Lopez and other VW employees concerning statements made during a recent civil court hearing. A number of GM executives had given evidence that directly contradicted sworn statements by Mr Lopez and others about their activities while still at GM.
Even though Mr Lopez signed a contract to work as production chief for Volkswagen on the evening of 9 March, Mr Gab alleged he still attended an international management strategy meeting at Opel's headquarters in Russelsheim the following day without telling anyone of the switch.
At that meeting, he said, Mr Lopez requested internal documents and asked for them and others still in his office to be sent on to a private address in Spain. Later that day Mr Lopez flew to Detroit and verbally informed Jack Hughes, GM's boss, of his decision to leave for VW.
The US Justice Department also confirmed it was investigating charges that Mr Lopez engaged in industrial espionage when he left GM.
The Washington Post suggested the Clinton administration had also entered the fray, deciding to make the dispute a 'test case against industrial spying by foreign corporations and governments'.
A General Motors official yesterday confirmed it had been contacted two weeks ago by FBI agents looking into the allegations against Mr Lopez.
Hamish McRae, page 25Reuse content