She was arrested on 2 September 2019 by Manokwari Police Resort without a warrant for bringing 1,496 small Morning Star flags through Manokwari airport. She is charged with Article 106 of the Criminal Code for participating as an orator in a protest on 19 August 2019 in Sorong which turned violent. She was a former Sorong city council member, she was fired as a result of her arrest. Not long after the arrest, a photo of her breastfeeding her infant baby behind bars went viral. Subsequently, access to see her was reportedly made difficult. Her older brother who came all the way from Sorong to see her also could not see her. Her brother made a public plea that he would go to prison in exchange of her so she could continue raising her infant baby and two other small children.
Her trial began on 13 February 2020. On 12th May 2020, the prosecutors in Manokwari, West Papua province, sought ten months in jail on charges of treason for her case. She remains in detention as the trial continues.
Ms Mandabayan is a former Member of the Sorong City Council; she was fired as a result of her arrest. Ms Mandabayan participated in peaceful protests on 19 and 27 August 2019 in Sorong City, including by delivering speeches. When she was arrested at Manokwari Airport on 2 September 2019, Ms Mandabayan had just arrived from Sorong City to attend a protest in Manokwari City that day.
She was sentenced to 9 months in prison for incitement attempt written and oral in public and not for treason on 27 May 2020.