Sam Lutfi: Harassing, Stalking Lindsay Lohan?!

Didn't see this one coming. Sources in Lindsay Lohan's camp say the person stalking her is none other than Sam Lutfi, Britney Spears' former "manager."

The stalker believed to be Sam has been harassing Lindsay Lohan through text messages and voicemail messages. We had no idea they were acquainted.

It's possible Lindsay didn't either.

Sam Lutfi is apparently still around ... and hounding Lindsay!

LiLo has been receiving ominous messages from someone who claims to be watching her. The Betty Ford Clinic is moving her to a more secure location.

Sam Lutfi was Spears' sole confidant just before she was placed on 5150 psychiatric hold. Britney's family believed Lutfi was enabling and drugging her.

Britney's conservators eventually obtained a restraining order against Lutfi, but he's recently been in close contact with none other than Michael Lohan.

In at least one text Lutfi sent to Lindsay, he falsely identifies himself as "Mike from TMZ" and warns her to distance herself from Dina Lohan or else.

Wouldn't you know it, the number on the text goes back to Lutfi.

Lutfi tells TMZ he didn't send the messages and that the people who rep Lindsay also repped Britney Spears and they're out to get him.

Yeah, because everyone thinks about you all the time, Sam.

Lutfi claims Lindsay has called him in the past, though sources connected with Lindsay Lohan say she doesn't know Lutfi at all. Lindsay's people have been in touch with Sam, warning him to stay away from her ... or else.