You need some more information. Go to town planning/building department and ask to review the file. You’ll need to know what if anything was there before this current structure was built, when the current structure was built and what the Ordinance required at the time in terms of setbacks.
If an old structure existed before zoning it is grandfathered. Sometimes older structures are more non conforming and rebuilds are permitted if they improve the situation (even if still non conforming).
Sometimes of course, the situation requires enforcement because someone built without a permit. Reviewing the file will help you find out what the situation is.