I'm not familiar with that incident, and couldn't find anything with a quick search; could you fill us in a bit?
That was related by Jack Hurst in his really good bio of Forrest! That's why his work is really outstanding for such details as that. Probably should mention what led up to black people keeping the Forrests penned up while waiting on the law to arrive. It's another where there are a few versions - never a consistent story with Forrest!
The murdered man was Thomas Edwards and he had been one of Forrest's slaves before the war - so he was a veteran. He was also said to be violent, enough so the other blacks were afraid of him. On the day of the events that got him killed, Forrest was directing the workers on digging a new ditch for drain-off due to an outbreak of cholera. Edwards did his part sloppily and Forrest directed him to re-do it correctly. Edwards then strode off the job and went home, where he commenced to beat his wife because he lost his job. People tried to break it up but their efforts only made him angrier - finally somebody ran to get Forrest.
Things get odd here. Forrest said he simply was passing by, heard a commotion and politely asked Mr Edwards to kindly stop thumping his wife, whereupon he was attacked. Well, I have a problem believing Forrest would arrive at such a situation hat in hand, polite as a church mouse...but he may have tried, things not being as they once were. Well, whatever he did or didn't do, things escalated faster than a speeding locomotive. When Forrest opened the door and told Edwards to knock it off, the man snarled he could do what he wanted with his wife, even beat her to death if he wanted, and resumed pounding her. Forrest then picked up a nearby broom and walloped Edwards, who turned on him and produced a knife. He took a slash or two at Forrest, who was backing toward the door, and somehow Edwards' fifteen year old niece - who was also getting a beating - got between the two men trying to stop it. Edwards made a stab at her, clearly intending to cut her up, and she ended up beside Forrest. Whether or not Forrest was trying to protect her, he was certainly trying to get out the door. Since the girl effectively blocked his escape route, the only other alternative was the kindling axe by the fireplace. Edwards saw it at the same time Forrest did and both men lunged for it - Forrest came up with it and swung. Edwards, seeing the hatchet coming, turned his head and got the back of his skull smashed in. He was dead instantly.
Since it was the back of Edwards' head, it appeared to most witnesses to be deliberate, not self-defense. Forrest wisely went home and proceeded to barricade himself and his family inside - which how they came to have a veritable arsenal inside the house. Blacks began appearing and it became ominous but turned out peacefully in the end with Forrest actually being arrested by the federal marshal.
At the trial, Mrs. Edwards swore up and down her husband never beat her, never laid a hand on her. Other testimony stated she was always being beaten and was, in fact, yanked out of bed for this beating while recovering from the previous one. She insisted otherwise. The niece testified to her uncle's violence and that he had tried to kill her before. She saw Forrest swing the axe in self-defense and stated her uncle had turned his head but had indeed been attacking. Self-defense. Forrest became the first white man acquitted by black testimony.