What was found
CAME TO AIRCRAFT AND POWERED IT UP WITH APU. DID FIRE DETECTION TEST, BAG LIGHT REMAINED ON. DID FIRE DETECT AGAIN AGAIN, LIGHT REMAINED ON. TOLD FIRST OFFICER TO CHECK PEEP HOLE, TOLD FIRST OFFICER TO LOOK AT BAG BAY. 1ST OFFICER SAID IT LOOKED LIKE SMOKE IN BAG BAY, EXTINGUISHING BOTTLE PUSHED, MADE CALL TO CFR.