Conan's standard problem-solving routine

The specific routine is like this: the body is found by a woman in most cases, then everyone arrives at the scene after her scream. As for the suspects, first there will be one who looks ferocious and not a good person, similar to Master Cao. But don't worry, this person is definitely a good person. There will also be another suspect who gets scared out of his wits and soils his pants upon hearing about the case, indicating that he is definitely related to the case. This person definitely knows a lot of inside information, but he is not the murderer, and later he will be killed by the real murderer in nine out of ten cases. There will also be a person who looks gentle and respectful, and seems to be an all-round excellent student since birth, maybe even studying at the conservatory of music... Sorry, I digressed. In short, this is a very good person, no doubt, and it must have been done by him.