The case involving government critic and former presidential hopeful Diane Shima Rwigara, her mother Adeline Rwigara and sister Anne Rwigara, is likely to be heard in camera when it goes to trial.
On Wednesday, prosecutors expressed fear that the content of the evidence, particularly audio recordings that were intercepted could be inciting if relayed publicly.
The trio is facing charges including inciting public insurrection.
The older Rwigara is separately accused of promoting sectarian practices and divisionism while Diane also faces charges of forgery during her presidential bid. They have denied the charges, saying they are politically motivated.
The court granted the prosecution's request to hear the pre-trial in camera due to the sensitivity of the audio testimonies and witnesses who do not want to be named.
A ruling on whether to grant the trio bail will be heard Monday, even as the prosecution said earlier that releasing them could jeopardise investigations due to the sensitivity of the charges.
The hearing has been marred by adjournments since it began, with the Rwigaras saying they have been denied their basic rights.