updated 12/19/2012 AT 10:30 AM ET
•originally published 12/19/2012 AT 8:00 AM ET
The day before he died, Jesse Lewis, 6, etched a brief, sweet note in the frost on his mom’s car door. “I love you,” it read simply in remarkably neat first-grade handwriting.
It was the last note she’d ever receive from him, Scarlett Lewis tearfully tells PEOPLE – and thankfully, she caught it on film.
“I said, ‘Oh, Jess, I have to take a picture of that,’ ” she says. “Thank God.”