María Eva Deria, daughter of two Montoneros militants who remain disappeared, passed away at 48 on Monday, the Grandmothers of Plaza de Mayo announced. Deria was searching for her sibling, who was born in captivity after their mother was kidnapped in late 1978.

“A sister that leaves without getting the hug she awaited. Until forever, dear Evita,” the Grandmothers of Plaza de Mayo said in a statement lamenting her death with “deep sorrow.” They added that her passing happened “soon and unexpectedly”

According to the statement, Deria worked at the Evita Museum, “where she poured her creativity and nurtured friendships,” as well as she did within the Grandmothers organization. She always participated in the organization’s activities, the Abuelas said.

“We can’t wrap our heads around this, because she had so much life ahead of herself,” they lamented. “With a big smile, profound eyes and extravagant curly hair, Evita stood out. Always with a cigarette on hand to accompany conversations and asking questions,” they described her.

Deria’s parents Hernando “Tito” Deria and Marta Inés Vaccaro were abducted from their house in Buenos Aires on November 28, 1978. Marta was seven months pregnant.

Survivors have testified seeing them at the clandestine detention center “El Olimpo,” in the Buenos Aires neighborhood of Floresta. There, fellow illegal detainees nicknamed Marta “La Gorda” (Fatty) as her pregnancy was very advanced. That was where Marta and Tito were last seen.

It is presumed that Marta gave birth to a baby during her time in “El Olimpo” between January and February of 1979. Eva, who had been born in 1977, was raised by her aunts Elba and Rosalía, and her grandmother Rosalía Martinoia de Vaccaro. Martinoia went on to join the Grandmothers of Plaza de Mayo. She was part of the organization’s board, and passed away in 2016 at 94.

“We want to especially hug her aunts, her friends, and each other to move forward, until we find her sibling and all the remaining grandchildren that are still missing,” the Abuelas said.

The Grandmothers of Plaza de Mayo have an entry about the Deria-Vaccaro family on their website, as they do with each of the families that are searching for a robbed child. IThey display a photo of Eva as a toddler and her mother, Marta, in the background, accompanied by a text Eva wrote for her sibling.

“This is the only photo of us together, on the sidewalk outside the house. Mom had you in her belly, there was also our great-grandmother Pita, and me, walking around.”