When I was a teenager I had a problem with my sister going through my stuff in my bedroom. So I took a regular sized baggie and filled it half up with Oregano and hid it under some t-shirts in my dresser drawer. Several days later I came home from school to some very freaked out parents and a sister standing in her room with an odd smile. I picked up the baggie from my dads hand, asked them to follow me, walked into the kitchen and poured the contents back into the fairly large but empty oregano container. I then explained what I had done and told my parents that if I every caught their 'precious little princess' going through my stuff again I would break her fingers. Needless to say she got in a world of trouble and never searched my stuff again. You should consider doing something similar. Someone can hide Oregano in their desk, some can hid talc power in a baggie, someone can hide some rock candy in a baggie, etc. This guy will think he's working in a Columbian drug lab. And when he goes off and the entire staff of the company stands up and tells what happened - maybe something will change.