The detention of Dionisio Zacarías - together with the other three Mayangna Indigenous Human Rights Defenders (Ignacio Celso Lino, Argüello Celso Lino and Donald Bruno) - were carried out without a judicial order at the time of their arrest. They were not informed of the reason for their arrest nor of their right to seek a lawyer or an interpreter, since their native language is not Spanish.

Following arrest, the four defenders remained unreachable for several months and were denied access to a trusted lawyer.

Since 2022, family members have only been allowed to speak with them for five to ten minutes through a glass window, using mobile phones provided by prison guards, without being allowed to touch or hug them.

As of August 2025, the four defenders continue to be arbitrarily detained in the “Jorge Navarro” Penitentiary Center, also known as “La Modelo”. They are in a serious situation and at risk of suffering irreparable damage to their physical and mental integrity; their lives are threatened. Since they arrived in the prison system in December 2021, they have been held incommunicado for long periods, chained in inhuman and degrading conditions, subjected to torture, cruel treatment and threats that have resulted in physical and sexual assaults. They have been denied medical attention, despite their extremely delicate state of health. In addition, custodians and other inmates - common prisoners - mistreat them when they speak Mayangna among themselves.