If you find yourself looking at a crime scene, your initial reaction may be to clean it yourself. You may want it to be gone as soon as possible and that's completely understandable. Here's some reasons why you shouldn't do that.
1. Fluids! Coming into contact with bodily fluids, especially blood, can be harmful. It can carry disease and pathogens that you just don't want on or near your body!
2. Invisible to the eye! If you don't take care of all of it, you can still recieve harmful effects. This means if you try and clean it and leave behind any traces of the scene (even germs and pathogens you can't see), your home won't be as sanitary as you think it is. You know how they say won't you don't know won't hurt you? Well in this case, it can.