Midnight Runner by Jack Higgins

After her brothers are killed one by one, oil heiress Kate Rashid --- now the richest woman in the world --- swears vengeance on all who have harmed her family. Never mind that they tried to assassinate the President of the United States, that villainy ran in their veins. They were her brothers, and their enemies must pay with their lives: British agent Sean Dillon. White House operative Blake Johnson. And the President himself ...