The Simple Errors in Crime Films

This is Steven Petrick Posting:

Most people, it seems, are able to watch shows and movies and accept what is happening.

I cannot.

I watch shows in which the innocent person is found over the murder victim with the gun in his (or her) hand, and thus the police know he (or she) is the killer.

No, he (or she) is not he killer. He (or she) is only a suspect. The fact that he (or she) has a gun in his (or her) hand and is standing over the murder victim does not in and of itself mean he (or she) fired the gun. Once you test him (or her) for gunshot residue, then you may have the killer. The caveat being that the scriptwriters might take that into account and have had the man (or woman) fire a weapon earlier in the day in an unrelated incident.

This is not high tech "CSI" stuff, the ability to do a gun shot residue test goes back to at least the 1930s, if not earlier.

So, yes, take the person into custody (he or she is standing over the victim after all), but that does not end the search for the killer. (Okay, if the movie/episode of the show is about corrupt cops looking to make an easy resolution to the murder or in cahoots with the murderer that is different.)

If the person is  holding his (or her) own gun, it is fairly easy to determine if it was fired recently (in the case where they drew their own gun and entered the room after hearing shots), and further in most cases whether or not the bullets in the victim match the rifling of the person's firearm. Again, old technology making it possible to determine if the individual's story has merit rather than assuming guilt and not looking for anyone else. (All this to allow the hero, whether the innocent individual or the cop or detective who believes in the innocence of the individual, to move on with the plot.)

It is possible in some cases these simple tests are left out of the script to save time and get the story moving, but because I know of them (and other things to look for in a crime scene) I have a difficult time enjoying what I am seeing. For example, there is a movie in which the innocent person is lured out onto a balcony with the victim, the innocent person is mad and has his own gun. A shot is then heard and the victim is dead. Everyone thinks the innocent person did it, but the fatal shot is actually fired from a window two stories above the balcony from a rifle. In short, the angle of  the bullet's trajectory, the size of the slug, the rifling of the slug, the lack of gun shot residue (even if there was blood splatter), and the fact that the innocent person's gun has not been fired all prove right then and there that he did not kill the victim, but the police pursue him for most of the rest of the film.