So he decided to leave a note for any future owners. "I guess I didn't want it to happen to someone else," Leventis explains. "It was our first house. We loved it. I felt horrible but I didn't want to see someone else get had the way we had. I was worried that if I left a note on the counter, it would get thrown away. I wanted to hide it where I knew someone would find it."
It's not clear who built the secret room, but Kerri Brown says she was told by Leventis that he discovered it during his short time in the house, thinking it would be a great hiding place.
Leventis says his daughters are feeling better but they still use an air compressor whenever they get a cold.
So where did the mold come from and who else knew about it?
Leventis bought the house from CCJ Properties, a local firm which flips homes in the Greenville area. "We were not aware of any mold," says Richard Robinson, the firm's owner. "We bought it from a bank, did regular repairs and painted the halls and floors. The only way I would have known is if I lived there for a while."
As for the Browns, they moved out and went back to renting an apartment. The couple ended up suing the broker and Fannie Mae, the home loan corporation, claiming that they knew about the mold but did not inform the Browns.
"Do I think we were deceived? Most definitely," says Kerri Brown. "People knew about something that could be harmful, especially to my child, and nobody had the guts to say anything about it."
Fannie Mae eventually agreed to buy back the home for the selling price and was dropped from the lawsuit.
"Throughout this difficult situation, we have worked to find a fair and equitable solution, including investigating concerns about an unusually high presence of mold in the home," said a Fannie Mae spokeswoman. "Our general inspection and the inspections conducted by the professional retained by the family did not initially reveal the presence of mold in the home prior to sale. We did offer to pay the cost to clean up the mold that was subsequently found. Following further discussions with all parties involved, we have agreed to buy back the property in question. We believe this is in the best interest of all parties involved, and it's unfortunate that the buyers encountered these problems."
The realtor, Sue Bakx, declined to comment to ABCNews.com. Her lawyer, Clark Price, says that she received a voicemail message about the mold but was skeptical about its veracity.
"She has been involved in foreclosed property sales for over 20 years and has heard this story again and again, in which somebody who loses the house is angry over it and spreads rumors about the house," Price said.
Price says that Bakx called Fannie Mae and was informed that they would not do anything based upon hearsay. And he says that the Browns were given full access to the house before they bought it and that they were informed in a contract that the house might have mold.
Though he insists that his clients did not owe the Browns anything, the parties finally settled in recent weeks and Price says, "We paid them their expenses and made them whole and apologized to them for not calling them."
Neither Price nor the Browns would disclose the terms of the settlement.
And even Price learned a valuable lesson. "When I bought my first house, my second house, my third house, I didn't have it inspected for mold," Price says. "Now, I will."