Cláudio Coimbra, 22, and Vadym Hrynko, 21, will remain detained in prison in Tomar.
Judge Carlos Alexandre justified the preventive detention due top reasons regarding the danger of disturbing the investigation and public order and also the danger of continuing criminal activity.
The two marines are accused of the crime of qualified homicide and three crimes of qualified offenses to physical integrity.
According to a source from the Judiciary Police (PJ), the two marines were detained on Monday night - along with a third suspect, a civilian, who has since been released by the Public Ministry (MP).
Agent Fábio Guerra, 26, died on Monday morning at the Hospital de São José, in Lisbon, due to “severe brain injuries” suffered as a result of the attack he was subjected to outside the Mome nightclub.