Lisbon\'s appeals court refused Thursday to extradite a convicted US murderer who was arrested in September after 41 years on the run on the grounds that he is now Portuguese. Washington said it was \"extremely disappointed\" with the decision in the case of the 68-year-old George Wright, who was found guilty of a 1962 murder in a US court -- and then hijacked a plane after escaping from prison. Wright was arrested on September 26 in Portugal, where he has been living for 20 years under the name of Jose Luis Jorge dos Santos, married with two sons now aged 25 and 26. \"The Lisbon appeals court ruled that he had Portuguese citizenship and will not be extradited,\" his lawyer Manuel Luis Ferreira told AFP. \"He is now free.\" Wright had been held under house arrest pending the court\'s ruling on a US bid to have him extradited. The decision could be appealed in a higher court, but only if an individual or institution petitions as a civil party, the Lusa news agency said, citing a juridical source. Speaking to journalists from his lawyer\'s office, Wright, who asked to be referred to by his adopted name, applauded the court\'s ruling. \"I am very pleased and I want to thank the Portuguese courts for having made the right decision,\" he said, adding that he has a \"clear conscience.\" \"These things belong in the past. I am no longer the person I was back then.\" The US Federal Bureau of Investigation had been searching for Wright since his August 1970 escape from Bayside State Prison in New Jersey, where he was jailed for a 1962 murder. For two years, Wright disappeared into the Black Liberation Army, a violent group of African American communists. Then on July 31, 1972, he was among five adults who hijacked a Delta flight flying from Detroit to Miami. They demanded a $1 million ransom for the passengers. When that was paid, they forced the plane to fly to Boston where it refuelled and took on another pilot hostage, then crossed the Atlantic to Algeria. The hijackers sought asylum there. Although the plane and money were seized by the Algerians and returned to the United States, the hijackers were only briefly detained. In May 1976, French police captured four of the gang -- but not Wright. The US State Department said while it \"respects the independence of the Portuguese judiciary,\" it was \"extremely disappointed\" in the decision. \"George Wright is a convicted murderer guilty of an extremely serious crime which falls squarely within the terms of our bilateral extradition treaty with Portugal,\" it said in a statement. \"He is a fugitive from justice. We expect Portugal to abide by its treaty obligations in this case.\"