False Impression

When an aristocratic old lady is brutally murdered in her country home the night before 9/11, it takes all the resources of the FBI and Interpol to work out the connection between her and the possible motive for her death - a priceless Van Gogh painting. It's a young woman in the North Tower when the first plane crashed into the building who has the courage and determination to take on both sides of the law and avenge the old lady's death.
Anna Petrescu is missing, presumed dead, after 9/11 and she uses her new status to escape from America, only to be pursued across the world from Toronto to London, to Hong Kong, Tokyo and Bucharest, but it is only when she returns to New York that the mystery unfolds.
Why are so many people willing to risk their own lives and others' to own the Van Gogh Self-Portrait with Bandaged Ear?