Answer:
Stonewall Jackson - mortally wounded at Chancellorsville, dying a couple of days later.
And there are so many different versions that it does look suspicious.
The popular, colourful version is usually the wrong one. This declares that Stonewall's party arrived back at camp in the evening, when the light was going, and their uniforms were covered in dust, so the sentry couldn't tell if they were grey or blue.
When he challenged each of them to give the password, one of them appeared to be answering in a fake Southern accent. This was an increasingly popular Union army trick that had cost the lives of many Confederate sentries, so he took no chances and decided to shoot the whole party.
I did read an eye-witness account of the fatal shooting, written by a Confederate officer - very badly written, but it was plainly not describing the incident as related above. And he did not suggest that the shooting was murder.
But it is accepted that a note was found attached to Stonewall's body claiming that he had been killed by his own men. Some say this was written by Stonewall himself as he was dying.
Popular legend has built Stonewall into a saint, but like most Confederate generals, he had almost as many enemies on his own side as in the US army.