Kazem Darabi’s Lebanese accomplice, Abbas Rhayel, has also been freed after serving 15 years in jail and was deported last week, prosecuting authorities told AFP.
A lawyer close to the case had earlier said that both men were to be deported on Monday night.
Darabi, 48, and Rhayel, a suspected member of the Iranian-backed Lebanese Hezbollah militia movement, were jailed for life for the 1992 murder of four Kurdish dissidents in a Greek restaurant in Berlin called “Mykonos”.
Their trial set off a diplomatic crisis between Europe and Iran because the German judges found that the restaurant killings had been carried out at the orders of Tehran.
Relations with Iran plunged to freezing point over the verdict because Tehran was furious for being fingered for sponsoring terror. Ambassadors from both sides were recalled for several months.
Germany’s federal prosecutors announced in October this year that the five years Darabi spent in jail before he was convicted counted towards his sentence and that he and Rhayel would be freed and deported to Iran.
The decision came as a surprise.
Under German law, life sentences are reviewed after 15 years but when the court convicted Darabi, it ruled that because of the severity of the charges, he should be held in prison for longer than the standard period.
Last year, the federal prosecutor’s office had given assurances that Darabi, whom Berlin has branded an Iranian secret agent, would stay in prison beyond the end of the year.
Iran has for years tried to secure his liberation.
Tehran attempted to negotiate his release in return for that of the German holidaymaker Donald Klein, who was jailed for violating Iranian territorial waters while fishing.
Klein was freed in March.
The case of Darabi was also frequently mentioned in German-brokered talks over the fate of Israeli air force navigator Ron Arad, who has been missing since October 1986 when his plane was shot down over southern Lebanon.
But the federal prosecutor’s office said on Monday that there was no prisoner exchange involved in the release of Darabi and Rhayel.
“This is not linked to any other case,” a spokesman told AFP.
Wolfgang Wieland, a member of Germany’s opposition Greens who handled secondary charges brought against Darabi and Rhayel during their trial, criticised the decision to release the two men.
“It will be interpreted by Iran not as generosity on the part of the West but as weakness,” he told AFP.
Israeli newspaper Haaretz has reported that Israeli Prime Minister Ehud Olmert called German Chancellor Angela Merkel in an attempt to persuade Berlin not to release Darabi.
But it said Merkel rebuffed his request, telling him that the authorities would follow the letter of the law.
