The Perfect Murder
Refraction is an interesting physical phenomenon.
Light waves coming from an object and into our eyes is how we see an object. Usually these light waves travel in straight lines. But when passing through an interface between two mediums of differing densities, they bend. This is called refraction. This is the reason the bottom of a pond appears to be shallower than it is. And why any change in its depth will look much smaller, when viewed from outside the water.
The clock ticked. He watched and waited. The clock ticked. The water poured. It felt like forever, but the young tenant was patient. The pond looked exactly the same as before. Almost. After 44 minutes, the water reached 2.5 cm below the top edge. Exactly the amount it had been before. He closed the faucet. Within the next 30 minutes he had calmly placed the Lilly pots back in place. He released the gappis (a variety of small fish which are commonly kept in ponds) that he had carefully put inside plastic bags with oxygenated water earlier on in the day. The task was complete. The “clean-up of the pond” was done, and the pond looked almost exactly like it did the day it was built. Almost.
The inspector had his constables search the house again as he spoke to the young tenant. The old lady had been missing for over two weeks now, and her family was giving up. The young tenant was the last person to have seen her and he gave his statement on his whereabouts when the old lady went missing for at least the fifth time. He had been at home in his room. He was studying for his exams. He had rented this room for a year and the old lady had been fond of him. There was no motivation for him to harm her. The man seemed friendly, maybe a little too friendly, which usually meant something fishy, but there was nothing at all that pointed towards this tenant as being responsible for the missing old lady. Where would he have taken her? And if he had killed her, where would he have hid the body?
Everybody noticed that the cement surface of the bottom of the pond looked clean. The young tenant had pointed it out and said he cleaned it “for the old lady”. No one noticed it was brand new. No one noticed it was about half a foot higher than it was before. Refraction took care of that.