This is more of a rumor, rather than a proven fact. It still has not been proven.
In the famous movie "Three Men and a Baby", there is a scene where you can clearly see a boy in the background. Some believe this is a cardboard cutout, but you can only see it for one part.
Before the boy is seen, as the characters pass the window, you can see a rifle. When they pass again, you see the boy. This leads people to believe that, if these rumors are true, the boy was shot with this rifle (whether it was murder, suicide, or an accident is really unknown).
I'll leave a video in the media.
00:05 - Rifle
00:34 to 00:38 - Boy