65-year-old Joanne Chesimard has become the first female on the FBI’s most wanted terrorists list.
She was convicted for killing State Trooper Werner Foerster at the side of the road on May 2 1973.
But she was later sprung from the New Jersey jail 1979 by a group of armed gunmen, and was found later to have been granted asylum.
The reward for information leading to the capture of Chesimard, now known as Assata Shakur, has now doubled to 2 million dollars (1.5 million euros).
Aaron Ford, the special agent in charge of the network, said there was no new threat posed by her, but he wanted to mark the occasion of the 40th anniversary of the crime by making it clear that the Bureau will not give up until she is brought to justice.
Ford added: “While living openly and freely in Cuba she continues to maintain and promote her terrorist ideology.