Tung Kuei Sen, charged with the 1984 slaying of journalist Henry Liu in Northern California, claimed he acted under orders from the Taiwanese government, a U.S. Embassy source said in Rio de Janeiro. The source, who spoke on condition of anonymity, said Tung was fighting extradition to the United States on grounds the Liu killing was a “political crime.” The U.S.-Brazil treaty prohibits extradition for that category of crime. “At interrogation and in written defense, (Tung) claimed he was sent to the United States by the Taiwanese secret service exclusively to kill Henry Liu,” the embassy source said. He said Tung stated Liu was “a double agent for mainland China and Taiwan.” The U.S. government expects a ruling on the extradition request by late April, the embassy source said. Tung, 33, was arrested by Brazilian federal police in September at the request of the U.S. government.