"Hi! I'm Cassie the bunny rabbit. I lived here too! (I'm potty trained!)," the note said. "I'm going to be the next Cadbury Bunny."
Jessica Monney previously shared photos of their bathroom before doing the demolition.
"If you know me, you know I love house projects. However, even I think I might be a little crazy for kicking off a bathroom remodel four weeks before I'm due," she wrote. "Bye bye bathroom!"
The image of the Shinsekis' note went viral after Alex Monney posted it on Twitter, gaining more than 11,000 retweets and 53,300 shares.
The tweet has since been deleted for unknown reasons.
However, the post gathered Twitter and Reddit users together to help the Monneys find the Shinsekis.
One Twitter user, named Jay Shinseki, tweeted back to say he believed the picture was of his younger brother.
Another Twitter user, Elissa Shinseki, also replied saying she was "at my grandparents' and working on figuring this out!"
Fox News reached out to the couple for comment, but did not receive a response.