She was placed under house arrest in the evening hours of 8 May 1948, together with her three children, Dunja, aged 54 months, Andrija, who was 27 months old, and Branko, who was five months old.

She was arrested on 17 May 1948. Having refused to testify against her husband, she was sentenced at a secret rigged political trial in 1951 to 12 years in prison, stripped of her civil rights for four years, and had her house in Pakrac confiscated. She was sentenced by a court of first instance and her sentence became executive immediately! She was not handed the verdict, receiving it only in 1957. She was convicted of helping the enemy (the Ustasha) during the national liberation war. By courtesy of the Party, she was paroled after eight and a half years, three and a half of which were served in solitary confinement. She was convicted only for being Andrija Hebrang’s wife. Knowing nothing about Andrija’s “enemy” activity, she was arrested as a witness - who knew too little. Psychologically and physically tortured at Glavnjaca, she signed a “confession” demanded of her by Milatovic and the comrades investigators. The nanny Gaga, shaken by the events, took her own life. In his book-indictment “The Case of Andrija Hebrang”, investigator Milatovic accuses Olga of collaboration with the Ustasha in an attempt to present the Hebrangs as a spy couple. Having served their sentences, the “betrayed” comrades spoke of Olga’s activity in the war! The 1951 verdict stated that she was Andrija Hebrang’s wife and not widow, if he had been killed by that time, and that she had two children. Milatovic and the comrades managed to convince Olga that her youngest child had died. After being released from prison Olga did not remarry.

The entire family’s name was changed to “Markovac” on 17 March 1958. She succeeded in reclaiming the name Hebrang only in 1983. The children never accepted the name Markovac and retained Hebrang in all Croatian documents.The Party’s administration in Belgrade, however, did changed Branko’s and father Andrija’s surname! 

Olga was under special surveillance of competent bodies and was prohibited from talking about the trial and the imprisonment. She lived in fear and had nightmares about Glavnjaca. In rare conversations about Andrija, she would cover the telephone with a pillow. She was unable to shake off the fear of Glavnjaca and Milatovic’s “investigative” methods until her death. Broken by years of stress, poverty, internal conflicts, and an uncertain future, she even caused a rift in the family, entering into a conflict with the children and Andrija’s sister Ilonka and her husband Pepi. In the 1980s she became more active in the search for the truth about Andrija’s demise. Her attempt at personal rehabilitation failed.

In the early 1990s the family, through the Croatian Democratic Union (HDZ), initiated the establishment of a Truth Committee, which led to the Croatian Parliament adopting in March 1992 a Declaration condemning the arrest and murder of Andrija Hebrang.

In the war she lost her first husband, a son and 54 family members. Most were killed as Jews, some as national liberation fighters.