Katt Williams is once again locked up ... after cops found weed and firearms while serving a search warrant at his house.
The Hall County Sheriff's Office in Georgia say the warrant was part of an investigation into Katt that began on March 1, after one of Katt's bodyguards claimed he was beat with a baseball bat and choked after refusing to "engage in criminal activity" at Katt's behest.
The bodyguard claimed Katt threatened to kill him ... but said the assault was carried out by others in the group.
When cops raided Katt's home Tuesday morning ... they found several firearms, and "large quantities" of marijuana.
Katt was booked for aggravated assault, terroristic threats, and false imprisonment. Cops say they will also add the drug and weapons charges.