The insanely wealthy man who reported $100,000 worth of watches and sunglasses stolen from his house told Lindsay Lohan she's not a thief, because "What's mine is yours."

TMZ broke the story ... Lindsay is the suspect in the theft.  The victim, Sam Magid, tried to recant his story but LAPD detectives say they have independent evidence to corroborate the theft and the investigation is full steam ahead.

We've learned text messages were sent between Lindsay and Sam over the last few days, and he says "I officially told Detective Rodriguez you can't take anything from me cause what's mine is yours."

Sam also told Lindsay he told cops the culprits were men.

It's also apparent Sam is obsessed with Lindsay, telling her he loves her and, "I will fight for you."