Martin Kober from upstate New York believes that his family owns a Michelangelo painting valued at around $300 million.
However, for the past 15 years the retired pilot has been frustrated by art experts lack of consensus about the work's authenticity.
He told the Associated Press: "It's tormenting now. I'm nobody, I'm not connected. I don't know if that's it."
The painting of Mary and Jesus had been a decorative piece in the family home until it was hit by a tennis ball - so it was moved behind a sofa for years.
Kober began researching the work in 2003 and he has since amassed a huge body of documents related to the painting.
His efforts have resulted in the support of Italian art expert, Antonio Forcellino.
He said: "I had assumed it was going to be a copy. In reality this painting was even more beautiful than the versions hanging in Rome and Florence. The truth was this painting was much better than the ones they had."
However others have dismissed it as a copy.
The painting is being kept in a secure location until a final judgement can be reached.