Cornelius Gurlitt, who made international headlines last fall when over a thousand works of art by masters were discovered in his Munich apartment, has died at age 81. The art was suspected to be stolen by Nazis during World War II and he only recently decided to strike a deal with German authorities.

German authorities began investigating Gurlitt back in 2010 and searched his apartment in February 2012. However, it wasn’t until November 2013 that they went public with their findings, announcing that around 1,400 works of art were discovered in his possession.

Gurlitt later said that he wanted the art back, but in April, he finally struck a deal to cooperate. He will return works that can be proven to be stolen pieces, but he could keep the rest.

According to the BBC, it’s not known who would take ownership of the remaining work, since it isn’t known if he has any heirs. Gurlitt, the son of Adolf Hitler’s art dealer, lead a reclusive life and only sold paintings if he needed money.

The LA Times reports that Gurlitt’s spokesman said that his death does end German officials’ investigation. He died in his Munich apartment with a doctor.

The paintings could be worth a combined $1.35 billion. Gurlitt also had a house in Austria, where 60 more paintings were found. Some of the work was by artists like Picasso, Matisse Gustave Courbet and others.