Can I sue a client that took an application I designed and developed and had another agency counterfeit it?

Question by Lounge9: Can I sue a client that took an application I designed and developed and had another agency counterfeit it?
I designed and developed a web site shopping cart application for a client three years ago. The user experience flow, graphic design and code of the application were all generated in iterative stages by myself from working with the client and based on their business requirements. After the application launched, I updated the application as products and prices changed, but the business relationship fell apart over time as the client ran out of money and wanted free updates. I went to the application’s URL today to find that the client had replaced my app with a new app created by someone else. The new app flows and functions exactly as the one I developed and a good deal of the graphic design, such as buttons, are exactly like those I designed in my app. My question is does the client have the right to take the app and have another developer essentially counterfeit it? Who owns the design and code? Our contract doesn’t state anything like this, so I want to know if I have legal ground to stand on. What should I put in future contracts to prevent this? I was originally planning on taking the code and design to resell and re-purpose it for other clients.

Best answer:

Answer by Sophie Smith
See an attorney. If you can prove it was your idea you should win

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