1. When somebody steals your idea/invention/product concept, it falls under "Patent Infringement" law;
2. When somebody steals your business Names/Trademarks (i.e, like McDonald name or its business name or logos, or even its colors scheme/patterns of red+yellow in some cases, etc. for example) to do their business or profits from your marks or any similarity of your registered marks (with Federal courts/USPTO) or your registered business name (with local courts/office), it falls under "Trademark Infringement" law;
3. When somebody steals your mental works (i.e., music pieces, songs, books, written software/programs, etc.), it falls under "Copy Right Infringment" law.
In this case, your is a "Trademark" case, and so you would need to contact a Patent&Trademark attorney specialized in Trademark litigation and as for 1-hour FREE consultation and go from there.
You/he will need send out first a "Cease & Desist" letter first, followed up by filing complaints in district or circuit court if they would not complied with, etc..