LIMA, Peru -- (AP) -- Lori Berenson, an American woman imprisoned for treason
 in Peru, arrived in the capital Thursday to prepare for a new trial following a
 military court decision that overturned the life sentence she was serving for aiding
 rebels.

 Berenson, 30, had spent nearly five years in prison before the top military court
 Lori Berenson, 30, spent nearly five years in prison for aiding rebels. The life
 sentence has been overturned.
 announced three days ago that it had decided to allow a new trial in a civilian
 court, a longtime demand of U.S. officials.

 But the state prosecutor handling the case on Thursday confidently predicted the
 New York native would receive a minimum 20-year sentence in the civilian trial.

 Television images showed police patting down a bespectacled Berenson, dressed
 in jeans and a burgundy sweater, before she was led aboard a commercial flight
 in the southern city of Arequipa, 475 miles southeast of Lima.

 Hours later in Lima, Berenson was taken in an armored vehicle led by a heavily
 guarded police motorcade to the maximum security wing of the Santa Mónica
 women's prison.

 Berenson was found guilty of treason by a military tribunal in January 1996,
 accused of helping the rebel Túpac Amaru Revolutionary Movement plan an
 attack on Peru's Congress.

 Since being convicted, Berenson has been held in two prisons. In 1998, she was
 moved from a high mountain jail cell to a prison in Arequipa after complaining of
 harsh prison conditions and poor treatment by guards.

 In an interview, state prosecutor María del Pilar Peralta said she had filed seven
 charges against Berenson, but declined to specify the charges.

 She described the state's evidence as ``abundant'' and able to clearly link
 Berenson to the now all but defunct Peruvian rebel group -- known by its Spanish
 initials, MRTA.

 Peralta said she expected the trial to center around new testimony by government
 officials held hostage during the rebel group's 1996 takeover of the Japanese
 ambassador's residence in Lima, during which they held 72 hostages for four
 months.

 Peralta said the officials would provide evidence implicating Berenson in the leftist
 guerrilla movement.

 The government officials ``supposedly talked with members of the MRTA who said
 she was a collaborator,'' Peralta said.

 U.S. officials have criticized Peru's judicial system, saying trials in its military
 courts, as well as those for terrorism in civilian courts, do not meet internationally
 accepted standards of due process.