Lindsay Lohan claims she has footage and text messages proving she's being stalked by a person who has been "threatening to kill" her ... and she's now going to the cops for help.
Lilo went on Twitter today and posted a photo of the man allegedly posing the threat -- saying, "This is the freemason stalker that has been threatening to kill me- while he is TRESPASSING! I'm actually scared now."
She continued, "all my fans, my supporters, please stand by me. g-d bless xxL."
We're told LiLo believes the man has been obsessed with her for nearly 4 years ... frequently dropping by her home and leaving weird gifts for the actress. We're also told he's been sending her "insane" text messages for the past few years.
Sources tell us Lindsay does not know the identity of the alleged stalker -- but she wants the cops to help keep the mystery man away ASAP.