civil suit for stealing IP?

Theft of intellectual property is in the legal category of "tort".  The statute of limitations for a tort suit begins usually when the harm is discoverd.  If you discovered the theft farther back than your state's statute of limitations, it's likely you may not be able to recover for theft of IP.  Your question says you are in Colorado.  The Colorado statute of limitations for this kind of tort is generally two years. Depending on the value of your IP, it may well be worth your while to hire a Colorado attorney for private consultation on this matter.  Getting a professional opinion on SOL questions should be relatively inexpensive.