Secret witnesses were "being influenced," the prosecutor told the court.
The witness placed them at the crime scene.
The witness implicated the six defendants during anonymised testimony.
Monday's hearing was cancelled after a defence lawyer called in sick.
Concluding pre-trial hearings, Judge Ibrahim Ali also granted the prosecution's request to seal evidence.
The slain blogger's family was allowed to attended a hearing for the first time.
Defence lawyers argued the murder charges were unclear.
No reason was given for the cancellation by court staff.
The PG office spokesman said Sunday's hearing was closed because it dealt with preliminary matters.
The PG spokesman told the Maldives Independent that the new criminal procedures law allows prosecutors to request secret proceedings "if they believe a circumstance that obstructs...