Lost

I've never had anything to do with forensic science but I dipped my toes in this morning. 
Yesterday the arm of Fiona's reading glasses detached. Luckily she found the minute screw which holds it in place. So we set to trying to reinsert it into the frame. Unfortunately it was a tricky and running out of time we went out. On our return some hours later the tiny screw had disappeared from the tray. It transpired that our daughter Ali had tried to do it but had dropped said screw on the kitchen floor. Not being able to find it she had given up. I tried to find it but decided to leave it to this morning to vacuum the floor floor being the easiest way of recovering it. This was the debris I was sorting through - but alas it isn't there. It has probably fallen between the floorboards.
I could not believe how much grime came up given I had only hoovered last week. As I was carefully examining each piece of grit etc I thought what an absorbing job it must be to do that for a living knowing that a small object might solve a crime and bring justice to bear. 
Fiona will be off to the opticians.