Knightley, 29, filed a harassment complaint with the NYPD against Landon Rust on October 2, one day after the Texas drifter disrupted the play "Therese Raquin" at Studio 54 on the first night of previews, reported New York Post.
"She was scared. She wanted to document the incident to start a paper trail in case this guy turns into a stalker," said one law-enforcement source.
"If he starts following her around and showing up where she is, then she can get an order of protection against him, but only with a paper trail," the source added.