She was the wife and only surviving immediate family member of comics writer and editor Héctor Germán Oesterheld.

[2] She met future comics writer and editor Héctor Germán Oesterheld while they were college students in 1944.

Her husband was a popular and influential writer of Argentine comics (known as historietas) including The Eternaut, Ernie Pike, Mort Cinder, and others.

At the beginning of the 1970s, Sánchez de Oesterheld's family became active in the leftist organization Juventud peronista, which was associated with militant opposition to the military junta.

[3] Sánchez de Oesterheld's life changed dramatically when her family became victims of the Argentine dictatorship between 1976 and 1983.

Some survivors of the secret military prison saw him alive in El Vesubio, and believe he was killed in or near Mercedes in 1978.

After the meeting, Beatriz left for Villa la Cava, in San Isidro, where she was a guerilla, but she never arrived.

Two days later, a stranger contacted Sánchez de Oesterheld with the information that Beatriz had been abducted by the military forces of the junta.

On July 7, Sánchez de Oesterheld was informed by the police that her daughter had died along with five other children.

She was last seen at the Police Headquarters of Tucumán, and it is believed that she was later taken to Campo de Mayo where she gave birth.

According to collected testimonies, on December 14, 1977, members of the police force killed Estela's husband “El Vasco” Mórtola.

[2] Sánchez de Oesterheld died of an acute myocardial infarction at home on June 22, 2015, at the age of 90.