Cops Called To Lindsay Lohan's House

Law enforcement sources tell TMZ, the man -- an older gentleman -- arrived at her home around 6:30pm and began knocking on the front door.

We're told Lindsay came to the door and asked what he wanted -- and the man responded cryptically ... that he needed to speak with her.

Unnerved, Lindsay asked the man to leave, but he refused, demanding she open the door. Police received a call minutes later about a trespasser on Lindsay's property. It's unclear if Lindsay made the call.