Former German Chancellor Helmut Kohl has told a court trying a former official for corruption that his government could not have been bribed.
Helmut Kohl's testimony could be key to a conviction
Mr Kohl's evidence has helped Holger Pfahls escape a charge that he accepted more than 2m euros (£1.3m) for helping secure a Saudi arms deal in 1991.
Telling the court he had personally approved the deal, Mr Kohl said the defendant had had no influence.
Mr Pfahls still faces charges of bribery and tax evasion.
The ex-junior defence minister and former head of German counter-intelligence has acknowledged accepting some money from a businessman, Karlheinz Schreiber, but says he did nothing in return.
Mr Kohl was the final witness in the trial, which was looking at a deal to supply 36 personnel carriers to Saudi Arabia during the Gulf War. He said his government had never been open to bribes.
"I have no indication of outside influences," Mr Kohl said. "I was never bribeable and never will be."
The deal, he said, was part of an agreement with the US state department.
Mr Pfahls said he accepted a bribe from an arms dealer
The BBC's Ray Furlong says Mr Kohl's evidence has a resonance beyond this case.
His reputation was severely tarnished in 1999 when it emerged his CDU party had been receiving illicit donations of money through a secret fund.
He has never revealed the names of the donors but the German police suspect one of them was an arms lobbyist who gave Mr Pfahls one million euros (£700,000) in cash shortly after the Saudi deal. More was put into a Swiss bank account.
Our correspondent says Mr Pfahls has offered no explanation of why he was given the money, just as Mr Kohl maintains his silence over his party's slush fund.
This trial has disappointed hopes that it might provide some answers, he adds.
Mr Pfahls, who could hear a verdict next week, went on the run in 1999 and was arrested in Paris and extradited to Germany last year.