Marilyn Manson is pulling out the big guns in his legal battle with ex-fiancée Evan Rachel Wood … claiming he has proof she used a forged FBI letter to drum up false allegations against him.

In new legal docs, obtained by TMZ, Manson argues his lawsuit against ERW never should have been thrown out … he says the fake letter she wrote from a real FBI agent clearly shows she cooked up a massive scheme to manufacture sexual abuse accusations against him.

Manson sued ERW and her partner, Illma Gore, back in March 2022 for intentional infliction of emotional distress and defamation … accusing the women of plotting to take him down and ruin his career.

The suit was dismissed, but now Marilyn’s appealing … he says ERW and Gore mounted a malicious campaign to harm him … namely, forging a fake letter from a real FBI agent that created the false appearance MM was under FBI investigation and his “victims” were in danger.

Marilyn includes what he says is the forged FBI letter as part of his latest filing … adding that Wood only filed a declaration that she herself did not forge the letter and did not really deny that it was a forgery.

What’s more, Marilyn claims ERW spread falsehoods about him to shore up a bogus narrative, solicited info from his former employees, hacked his accounts, manufactured fictitious emails and “swatted” him at his home to draw more attention to her lies.

Marilyn also says the lower court judge in the case did not even take into consideration the fact one of his accusers recanted her false allegations of abuse and detailed how she felt pressured by Wood into lying about Manson.