Years ago my partner licensed 3 of her paintings to a company to be published as posters, which she received initial royalties for, but 3 years ago the royalties stopped and we were told the company went out of business. Last week a friend spotted those 3 very distinct images re-worked into a large mural on the wall of a NYC cafe. Photos prove clear copyright infringement. My partner knew nothing about her art being used for murals, was never asked permission or paid anything for that use. Who can she sue for infringement - the muralist who copied the art, the cafe owner for unauthorized use of stolen images, the poster company who licensed the art (if proven they illegally sold or sub-licensed her images to the cafe or muralist) or could all three parties be held liable?