MEXICO CITY -- The gray-haired housewife has organized hundreds of protest marches, gone from hunger strikes to a seat in congress and argued face-to-face with presidents.
Just as she has been transformed by the 26-year search for her son, Rosario Ibarra de Piedra has seen Mexico change: Democracy has put a conservative opposition leader into the presidency and leftist rebels have emerged from jungle hide-outs and secret jails into the center of the media spotlight.
President Vicente Fox announced Nov. 10 that he would appoint a special prosecutor to investigate the cases of 570 leftists who disappeared during a government counterinsurgency campaign in the 1970s, among them Ibarra's son, Jesus.
And the government's human rights commission said Thursday it will release a 3,000-page report on 530 of the missing activists early next week.
Many people see that as a result of Ibarra's persistence.
Over three decades, she has helped win the release of hundreds of political prisoners and contributed to changing public attitudes that led to the downfall of Mexico's once-imperious presidential system. She has twice won seats in congress.
Yet the tiny, tireless woman has never been able to find out what happened to Jesus Piedra, a medical student believed to have been kidnapped by police in the northern state of Nuevo Leon on April 18, 1975.
Half said murdered
Mexican news media have reported on partial, leaked versions of the human rights office report that suggest about half of the "disappeared" were murdered and secretly buried.
Several years ago, a retired military officer said that Jesus Piedra -- thought to be a member of the Maoist September 23 League -- was picked up by police, tortured, killed and disposed of in a lake.
Ibarra said she believes her son was imprisoned at a secret military jail. After that, she doesn't know what happened. But she said she won't stop until those responsible are punished.
"We want the law to work," she says.
It hasn't so far. For decades, presidents refused to release information on the missing, apparently to avoid embarrassing the army or revealing abuses by secret police.
When Fox became the first opposition candidate to win Mexico's presidency, having publicly embraced Ibarra's cause, he dismantled parts of the system that had given his predecessors almost unlimited power.
But Fox initially balked at delving into old crimes, arguing Mexico "should look to the future, not the past." Then, following the October murder of a prominent human rights lawyer, Fox changed his mind.
For Ibarra and for dozens of other mothers in her Eureka! group, Jesus and the other "disappeared" remain alive.
"Twenty years ago, I told a government minister, 'If you give me my son, I'll go home and shut up,"' said Ibarra. "'But if you don't, people will know who Jesus Piedra is 500 years after they've forgotten the name of the president of Mexico."'
Today, Jesus' soft, open face -- a 21-year-old frozen in time in a black-and-white photo -- is almost as widely recognized as that of Luis Echeverria, the president in 1970-76 who now lives in self-imposed obscurity.
Another image -- also full of history -- hangs in her Mexico City apartment: a poster showing Ibarra embracing Subcomandante Marcos, leader of the leftist Zapatista rebels in Chiapas state. The image of two leftist icons, one from the 1970s, one the 1990s, is a vivid illustration of how the left has changed.
Instead of operating with clandestine cells, kidnappings and bombs in a Maoist-style insurrection as rebels did in the 1970s, the Zapatistas masterfully played the media game and influenced public opinion far beyond their brief armed uprising in January 1994.
Ibarra calls the Zapatistas "a gleam of hope" for Mexico. "They are different from any other guerrilla movement that came before, because they don't want to take power."
Ibarra, who has three other children, seems younger than her 73 years. What keeps her going through things like a 26-day hunger strike? "A mixture of pain, and love. It's a mother's love, and that never ends."
The mothers in her group are active, sometimes holding parties where each brings a recording of her missing child's favorite song.
"We take care of ourselves," she said, "because we don't want to die without finding out what they did with our kids."