Twenty-five years ago, news broke of the biggest art theft in history. Boston's Isabella Stewart Gardner Museum was missing major artworks, taken in the middle of the night by two men disguised as Boston police. It was a stunning loss.

The FBI says the two men suspected of actually swiping the art are dead. Their names have not been released. The 13 stolen artworks, by the likes of Rembrandt, Degas, Manet and Vermeer, and worth about $500 million, are still missing. There is a $5 million reward offered for information leading to their return.

Gizmodo has summarized the five big theories swirling around who did it:

1. Boston mobsters

2. The IRA

3. Notorious art thief Myles Connor and his network

4. The French-Corsican mob

5. Inexperienced criminals who destroyed the work

Read through the theories on Gizmodo and email info@artfixdaily.com with your vote for the one you think did it.