Lori Berenson, a Lima resident, was arrested in 1995 and sentenced to life in prison for MRTA links. She appealed and had the sentence reduced to 20 years.
A parole decision outraged Peruvians and was swiftly followed by an appeals court judgment that struck it down amid accusations that Berenson's appearance with her 15-month-old son was a ploy to win public and judicial sympathy.
Justice Minister Victor Garcia Toma said authorities could have avoided the scene where Berenson was filmed holding the boy, Salvador, while being taken into custody. "Certainly a baby can't be used to create a masquerade of victimization," said Toma.
Berenson married a prison inmate, Anibal Apari, who later became her defense lawyer although the couple separated.
Apari dismissed the criticism, saying Berenson happened to be with her son at a meeting at the U.S. Embassy when the court ordered her arrest. He accused the media and high-ranking Peruvians of fomenting a hostile attitude to Berenson.
"Whatever she does, there are always going to be people who regrettably hold court in the media, who feed a climate of confrontation and ill will toward Lori," Apari said.
Berenson won her parole after serving 15 years of her 20-year sentence, but the prosecution argued the 15-year term hadn't been completed. Berenson has apologized for her actions, though maintained she never engaged in any direct violent activity.
The appeals court annulled an earlier decision granting parole, observing the lower court hadn't received proper police verification of the address where Berenson would be living upon her release.
The government also asked the appeals court to consider the prosecutors' argument that Berenson was prematurely granted parole after 14 years and five months in prison, instead of the required 15 years.
MRTA was the less violent of the two major militant groups in the 1980s, its actions mostly overshadowed by brutalities perpetrated by Maoist rival Shining Path.
MRTA's last major action led to the 1996 takeover of the Japanese ambassador's residence in Lima, when 14 members of the group occupied the building and held 72 hostages for more than four months. A military operation in April freed all but one of the hostages that remained in captivity at the time. The rescue became a high point of the presidency of Alberto Fujimori before his fall from grace and imprisonment for corruption and human-rights violations.