Nonetheless, the movement was hampered by a series of events including serious strategic gaffes and the betrayal of high-ranking Tupamaro Héctor Amodio Pérez, police officers who were granted liberal repressive powers to deal with Tupamaros. Sendic was arrested in Uruguay on 7 August 1970, and remained in prison until his escape 6 September 1971. The mass escape of the year 71 caused the civilian authority to call the Uruguayan military to lead the operations (so far being undertaken by the police).