So far, 14 senior officers, seven middle-level officers and 12 casual workers have been interrogated.
A source at the BNI told the Daily Graphic that the initial interrogation was to help establish if there was criminal intent behind the fire.
The outcome of the initial interrogation, it said, would determine the direction of investigations.
On January 13, 2015, an inferno engulfed the CMS of the Ghana Health Service (GHS), destroying medical supplies.
The fire started around 9:45 a.m. and for many hours firefighters battled to douse the flames.
The Ghana National Fire Service (GNFS) had to mobilise 12 fire engines and two support tankers, in addition to support from the fire brigades of the Ghana Ports and Harbours Authority (GPHA), the Ghana Armed Forces and the Tema Oil Refinery (TOR), to control the blaze.
The cost of the items destroyed has been pegged about Ghc237.7 million. The facility has not been insured to recoup the loss.