Nzabonimana was arrested in Kigoma, Western Tanzania on Monday and was transferred to the UN Detention Facility on Tuesday night.
According to an indictment read out in the courtroom, it was alleged that the accused played an important role in the massacres of Tutsis in Gitarama, central Rwanda, his native region.
He is also alleged to have ordered mayors to organize massacres in their communes and the accused personally traveled to inland areas to ensure that farmers carried out the orders of killing ethnic Tutsis.
The prosecution alleges that between April and July 1994, in Gitarama, the mayors who had refused to carry out the directives to commit massacres of Tutsis or those who had not shown zeal in the execution of these directives were reprimanded or even sometimes physically abused before being dismissed or being eliminated.
The presiding Judge Dennis Byron has ordered the Registrar to set a date for hearing of the case.
Nzabonimana formed part of the fugitives for which the US government had allotted bounty of up to five million US Dollars to whoever would offer information leading to their arrest.
According to the representative of Rwandan government to the ICTR, Mr. Aloys Mutabingwa, the arrest was ‘'a big catch...I must appreciate the level of co-operation by the Tanzanian police to the ICTR."
The ICTR Prosecutor, Justice Hassan Bubacar Jallow said:' this is a significant arrest given the profile and level of involvement in the genocide by the accused.
Of the six most wanted people, Nzabonimana is the second to be arrested after Augustin Ngirabatware in Germany last September.