Germany's highest court said Friday it has rejected a complaint by a US citizen against his extradition to California, where he could face a life sentence without parole on murder charges. The defendant, Michel Azarg, had argued that the threat of life in prison without the possibility of release on parole for good behavior was a violation of his right to "humane punishment." In a ruling dated July 6, the German federal constitutional court upheld that argument but said the law in California, where the suspect is facing murder charges, allows the governor to shorten his sentence or grant him parole. It said that extradition could only be stopped when the suspect faced "cruel, degrading or unbearable punishment" in a foreign country. Azarg, 36, is suspected of storming, together with three other armed men, a party with 17 people in Marin City in northern California on January 9, 1997 and killing the host with seven gunshots. He fled to Germany and was arrested in July 2004 near the western city of Cologne on a US arrest warrant. US authorities said a dispute over drug deals was behind the slaying.