Even simpler - Lois's Jeep was positively IDed in a hit and run and found in the repair shop Lois frequents - no one saw her there but there was a note saying 'fix this' on the windshield.

Big Apricot Superman Movieverse
The World of Lois & Clark
Richard White to Lois Lane: Lois, Superman is afraid of you. What chance has Clark Kent got? - After the Storm