I think this is not the first interaction you had with this guy ? You, at least, know of him and have seen him in the building. Is he just trying a strong arm take over or does he feel you and he have an old score to settle ?
I would never have gone public with it. But if someone threatened me and I had no way to extricate myself from my property I owned I would think of carefully of my options. But murder is one thing I would not do, as I answer to someone higher on that matter, and also no property is worth a possible 3 years in DR prison, and he may well have backup.
But there are other means that could be brought to bear to convince him in the error of his ways of making threats.