Peru’s supreme court has overturned the pardon of former president Alberto Fujimori and ordered his immediate capture and return to jail.

Just nine months after Fujimori was granted a humanitarian pardon, the country’s supreme court has ruled the former president must complete his 25-year jail sentence for authorising death squads, overseeing rampant corruption and vote-rigging.

The former president Pedro Pablo Kuczysnki pardoned Fujimori, 80, on humanitarian grounds last Christmas Eve in a move widely seen as a political deal to save himself from impeachment on corruption allegations.

The move triggered massive street demonstrations and prompted outrage among relatives of victims of human rights abuses during the former strongman’s rule.

In a ruling on Wednesday, Judge Hugo Núñez said the pardon, which was granted for medical reasons, lacked legal foundation and had been pushed through too quickly.

He added that Fujimori, who governed Peru between 1990 and 2000, should not have been freed as he did not suffer from a terminal illness, which was one of the reasons given for his medical pardon.

“This is the saddest day of our lives,” the former president’s daughter and political heir, Keiko Fujimori, told journalists outside her father’s home in Lima.

“A judge in our country took away my father’s freedom saying because he is not dying, he doesn’t have the right to a humanitarian pardon, and secondly, because there were procedural errors the one who must pay is my father.” She said her father’s lawyer will appeal the court’s decision.

Alberto Fujimori is the figurehead of the party which dominates Peru’s congress and a deeply divisive figure in the country. The hard-right populist political movement he began in the 1990s continues under the leadership of Keiko Fujimori who commands an absolute majority in Peru’s legislature.

She has twice lost presidential elections in 2011 and 2016, the second time by the narrowest of margins to Kuczynski, who resigned in March rather than face impeachment for alleged corruption.

“This is revenge,” Carlos Tubino, a congressman for Fuerza Popular, the party led by Keiko Fujimori, told journalists in Peru’s congress.

“They want Fujimori to die in jail for the satisfaction of people who have no humanity in their heart.”

Erika Guevara-Rosas, Americas director for Amnesty International, tweeted that the court had respected the “rights of the victims and their families”.

“The humanitarian pardon granted to Fujimori violated the obligations of the state to investigate, prosecute and punish those responsible for serious human rights crimes,” she added.

The pardon was appealed by the families of the 25 victims of two death squad massacres for which Fujimori was sentenced to 25 years in prison in 2009.

“This ruling re-establishes the right to justice for the families and makes completely clear the illegality of the decision of then president Kuczysnki,” Carlos Rivera, a lawyer at the Legal Defence Institute, told local television.

“What the families of the victims have shown that this pardon was not humanitarian but a political pact,” said Marisa Glave, of the leftist Nuevo Peru party.

Peruvians remain bitterly divided over Fujimori’s legacy. His supporters credit him with laying the foundations of the country’s robust economy and defeating the brutal Maoist Shining Path movement.