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(KMOV) -- Someone is buying up hundreds of parcels of land in St. Louis, but who and why are a mystery.

Many of those buildings are now empty and decaying.

One of the homes was once owned by Mark Twain's uncle.

(KMOV)

North St. Louis neighborhood

It's one of many north St. Louis properties, purchased by a company called Blairmont which is causing a lot of concern.

Blairmont, and several apparently related companies, have purchased more than 500 parcels of land in north St. Louis.

Residents are concerned that these companies may develop new, modern housing and that they will lose the historic homes and features of the neighborhood.

Residents can't reach anyone with those companies.