Lindsay Lohan -- PURSE RETURNED ... Minus $10,000

Lindsay Lohan's purse has made it back to its rightful owner safe and sound -- passport and everything -- but sources tell TMZ, the thief kept one massive jackpot ... $10,000 in cash.

TMZ broke the story ... Lindsay's $5,000 Chanel purse was stolen last night from a Hawaii house party -- and inside the bag ... her passport, important probation docs, and a boatload of cash.

Sources tell us, Lindsay stayed long after police left -- driving the entire party into a frenzy for hours looking for the purse -- and up until this morning, she had come up empty.

But that's when one of her friend's eyed a suspicious-looking local, and asked if he knew where the bag was. We're told the local denied everything, but showed up with the bag minutes later ... claiming he found it on the street somewhere.

We're told Lindsay was so ecstatic to have the bag back, she didn't bother asking questions -- despite the missing $10,000.