What these criminals would do- if they were real researchers- would be to go to Dealey Plaza in late November and take their own pictures, trying to duplicate Doorman's image, including his shadows.
Why limit yourself to trying to refute my work when the most decisive thing would be to go there and demonstrate that a neck shadow can make a round t-shirt look vee-shaped and without the slightest giveaway that there's white fabric beneath the sea of black.
If you think that's what it is, then prove it by going there and reproducing it. If you can travel to Texas to commit crimes, then why not travel to Texas to do research? Or won't your employers pay for that? Regardless, you have the means. You have the opportunity. You certainly have the time. And nothing is stopping you.
So, why doesn't he do it? It's because he knows he can't do it. He knows it is not going to turn out well. It is not going to support what he is claiming.
That's why he doesn't do it, and that's why nobody else does it either.