After her sister's murder Helen Mack Chang became a reformer

It was late February 2003 and finally the Mack family had their government cornered at the sort of hearing for which they had waited more than a decade.

Their elusive quest for justice in the murder of Myrna Mack Chang had been thwarted by the legal system at home in Guatemala. But they were in a new arena now, a place where they hoped for a fair resolution.

But on day two of the trial, Myrna Mack Chang vs. the State of Guatemala, held at the Inter-American Court of Human Rights in San Jose, Costa Rica, the family's quest again looked to be a forlorn affair.

Pursuing her home country for its state-sponsored slaying of her sister, Helen Mack Chang looked on helplessly as representatives of the Guatemalan government walked out of the courtroom, refusing to concede full responsibility for the death of her sister.

The courtroom seemed suspended in time, as a tearful Helen Mack Chang rose from her seat and chased down one of the men, beseeching him to return. It was an abiding image of the trial – emblematic of the perseverance and fortitude of this Guatemalan human rights warrior.

Today she has become a luminous figure in Guatemala at a time when that country is watching an unfolding courtroom drama involving the genocide trial of former Guatemalan dictator José Efraín Ríos Montt. He is being retried after his original conviction was thrown out in a case related to mass atrocities committed on indigenous Mayans during his time as president of Guatemala in the early 1980s.

Myrna Mack Chang was brutally stabbed to death on a Guatemalan street on Sept. 11, 1990, at the hands of a government agent.

It was a state-sponsored assassination, silencing her work as a social anthropologist charting the struggles of innocent members of the country's indigenous population caught in the crossfire of a brutal civil war. The San Jose, Costa Rica, court duly held the Guatemalan government responsible and ordered reparations. And the country of Guatemala later acknowledged responsibility and apologized to the Mack family.

For some, the long fight for justice may have ended there. But not for Helen Mack Chang. She was bent on obtaining justice for others who had suffered during and after the brutal 36-year Guatemalan civil war (1960-1996) that ostensibly pitted government forces against left-wing guerrillas. Some 200,000 people died during the conflict.

Moreover, Helen wanted lasting justice in the form of changes to the way Guatemala operated.

Through the Myrna Mack Foundation, Helen has become one of the most prominent advocates for human rights in Guatemala, collecting numerous international awards for her work. One such prize, the Right Livelihood Award, dubbed the alternative Nobel prize, helped her form the Myrna Mack Foundation, her work's center of gravity.

In another crusade, she was an adviser on the case brought against the Guatemalan government for the murder of police investigator José Miguel Mérida Escobar and cases involving the forced disappearance of other citizens. Mr. Merida apparently suffered the same fate as Myrna Mack Chang after discovering who was behind her death.

In recent years Helen Mack Chang has continued to seek judicial and police reform. Working alongside members of a government that once watched her every move, for 18 months she was on a presidential commission designed to bring changes to the country's police forces. She was honored for her work by current Guatemalan President Otto Pérez Molina, a military commander during the civil war years who himself has attracted accusations of being involved in mass killings.

She also saw her efforts help lead to the disbanding of the presidential security detail that had been behind Myrna's death. Helen is also founder and coordinator of the National Commission to Support the Strengthening and Monitoring of Justice in Guatemala.

"This year is the 25th anniversary of Myrna's murder," Helen says. "I find myself again in a case concerning the murder of the police investigator in the case of my sister.

"Since the foundation was formed we have tried to encourage citizens to know their rights and defend them, and just by participating build a genuine rule of law in Guatemala."

Myrna's daughter, Lucrecia Hernandez Mack, was a teenager when her mother was murdered. She recalls the quarter-century struggle undertaken by her aunt Helen. She sat beside Helen that day in the San Jose courtroom and has been with her at other critical junctures since the day Myrna was slain.

"I remember going into the morgue, the night my mom died," she says. "Several friends and relatives were there, they were all very quiet. We all knew why my mother was killed, and we were all afraid. Some days later my aunt was asking the police about the investigation. She wanted to know the truth, she wanted justice, she wasn't afraid.

"I've often told my aunt that maybe she was too unaware of the political situation in Guatemala, that she didn't really know what she was getting into, that she was naive. But if naivety was there, it was only for a little while, because it quickly became a profound commitment, personal and social.

"After struggling with my mom’s judicial cases for almost 15 years, she took on the responsibility of starting the police reform. She then sought justice for the families of the disappeared ... and now she wants to find the authors of ... Mérida's assassination.

"Guatemala has not been easy on her, but she has decided not to let go [of it] that easily either."