Sources close to the Lindsay Lohan stalking incident say it's quite serious. Apparently people in the know agree, because the FBI is now involved.
Agents are now in possession of threatening and harassing messages sent to Lindsay and members of her family. Sam Lutfi may be responsible.
Lohan has been receiving a variety of ominous messages ... some of which her camp thinks came from Britney Spears' former manager/enabler.
STALKED: Hopefully the FBI puts a stop to it. [Photo: Pacific Coast News]
Sources also say her mother, Dina Lohan, and her brother Michael Lohan, Jr., have also been receiving strange messages in the past few weeks.
Some of them badmouth Dina, others warn her to stay away from Lutfi and Michael Lohan, Sr., who have reportedly been in contact as well.
It's all very weird. It's also unclear if the messages are in any way related to the psycho photographer that rehabbing Lindsay is so terrified of.
DiLo has passed along the info to the FBI, which is also looking into Ali Lohan's identity theft case, and officials say they are "looking into it."