In the first book about their experience, Keith Stansell charges Betancourt risked the Americans' lives by telling guards they worked for the U.S. Central Intelligence Agency, The Daily Telegraph reported Friday.
Stansell, 44, a former Marine, said the Colombian politician who holds dual Colombian-French citizenship was haughty, self-absorbed and stole their food.
"I watched her try to take over the camp with an arrogance that was out of control," Stansell said. "Some of the guards treated us better than she did."
Betancourt has declined to comment on the allegations.
Stansell and the other two Americans, fellow contractors Thomas Howes and Marc Gonsalves, take turns in the book narrating their experiences as hostages of a Colombian terrorist organization.
They were freed last July along with Betancourt and 11 Colombians by military agents posing as humanitarian workers.