An Argentine judge has ordered the arrest of the head of the human rights group, Mothers of the Plaza de Mayo.
Hebe de Bonafini has refused twice to appear in court to give evidence over the alleged embezzlement of millions of dollars from a low-income housing project.
Mrs Bonafini, who is 87, is not personally accused in the case.
Her organisation has been leading the fight for justice for victims of the 1976-83 military regime in Argentina.
Later, it became a close ally of the former president, Cristina Fernandez de Kirchner.
Police were dispatched to escort Mrs Bonafini who has refused twice to appear in court to give evidence.
But she apparently managed to avoid them and boarded a mini-van bound for the Plaza de Mayo.
The square in front of the presidential palace is the site where the Mothers and their sister group, the Grandmothers of the Plaza de Mayo, have marched in protest every Thursday since 1977.
Mrs Bonafini has two sons who were “disappeared” by the military government.
More recently, the Mothers have said that they want to do some of the work their children, who were mostly left-wing activists, would have ended up doing if they were alive.
They launched a $53m (£40m) programme to build housing, schools and health centres in low-income neighbourhoods.
The project was abruptly halted in 2011. Prosecutors are investigating the diversion of millions of dollars from the project.