IT was murder - committed to hide allegations of high-level corruption in Kenya.That is the conclusion of John Troon, who was a detective with Scotland Yard when the Kenyan government asked him last year to investigate the 1990 death of Foreign Minister Robert Ouko. According to earlier testimony by Mr. Ouko's sister, Dorothy Randiak, in the ongoing inquiry into his death, Ouko had been preparing a report charging that Nicholas Biwott, one of President Daniel arap Moi's most powerful aides, was taking millions of dollars in bribes from an Italian firm wishing to do business in Kenya. Some international donors have cut or are considering cutting aid to Kenya over allegations of corruption by Kenyan officials, including Mr. Biwott. Mr. Troon made no statement of blame in Ouko's death, and Biwott's lawyers have denied any wrongdoing on his part. But Troon said the government had blocked his efforts to interview Biwott, forcing him to close the investigation prematurely. Troon says that had he been able to pursue the case, "the truth may have come out." In his testimony Nov. 11, Troon described Ouko as a man of "undoubtedly high integrity in morality and honesty." Troon also linked the murder to a dispute he believes Ouko got into with Biwott and Mr. Moi during a trip they made to the United States just prior to Ouko's death. The dispute involved foreign bank accounts allegedly held by Biwott and other Cabinet members, according to a sworn affidavit by Ouko's brother, Eston Barak Mbajah. "The relationship became so strained throughout their visit, that on their way back to Kenya, they were not on speaking terms," the statement said. Mr. Mbajah made his statement in the US, where he fled after his brother's death. Mbajah also claims his brother left him a note prior to his death, saying Hezekiah Oyugi, the Kenyan official in charge of internal security, wanted to help him escape Kenya, because Moi was "not ready to forgive him" because of his corruption allegations. Mbajah says his brother was suspicious of the escape plan, which involved taking him to Mr. Oyugi and Biwott. Troon says Ouko was picked up by occupants of a white car Feb. 13, 1990. Troon says he did not learn who was in the car, but Mbajah names four people in his statement, one of whom was a government official, without saying how he knew who they were.