The Fourth Angel (2001)

Plot: Jack Elgin, the European editor of the Economist magazine, is flying to India with his family for a working vacation. En route, the AM Airlines (an American company) flight is hijacked, with the hijackers demanding $50 million in ransom. After the moneys are paid, the hijacking goes awry on the ground in Cyprus, where fifteen people end up dead, including some of the hijackers, Jack's wife and two teen-aged daughters, leaving him and his adolescent son Andrew among the survivors. Jack later learns that the two sole surviving hijackers, who were captured and who are part of a Serbian terrorist group called the August 15th Movement, have secretly been released without charge. An incensed Jack tries to find out who was behind their release, his only initial clue being that one passenger who he saw executed on board the plane is not listed among the casualties. One of the people with who Jack meets is CIA agent Henry Davidson, who is based at the American Embassy in London. Davidson, who officially states that not much can be done through legal channels, encourages Jack, off the record, to use his journalistic skills and contacts to find the hijackers and their backers, and if he finds them to use his own sense of justice. As Jack tracks the hijackers, the FBI assigns agent Jules Bernard to lead the case in conjunction with Scotland Yard's anti-terrorist group. When a series of killings happen in London that seem associated with the terrorist group, Bernard believes that finding who is committing these murders will help solve the case. As Jack's killings and Bernard's investigation start to converge, the information they individually gather may piece together the entire picture of why the hijacking took place.