If there was a breakthrough in technology where police can read people's thoughts?

If someone were thinking of committing a crime, should they be arrested and charged before they commit the crime? The thought would be proven through certain brainwaves and thoughts of wanting to commit the crime, recorded by the technology. Would you be in favor of such law enforcement? This way, the gap between criminals and non-criminals will become even more obvious and the crime-rate will drop very quickly.