Deciding which ghost

Me and my friends played on professional for the first time last night we both got 2 out of 3 evidence but struggled to get the final piece. It was between a Shade and Jinn and we chose Jinn however, we were wrong. There was no Ghost Writing Evidence so I’m unsure as to how? I stayed in the room alone with the book open and spirit boxing for like 3 minutes but still wrote nothing in the book. Any recommendations?