When any merchandise on which the duty has not been paid or which was imported contrary to law is found in any building upon or within 10 feet of the boundary line between the United States and Canada or Mexico, such merchandise shall be seized and a report of the facts shall be made to the Commissioner. With his approval the building or that portion thereof which is within the United States shall be taken down or removed. The provisions of subpart B of part 162, of this chapter shall be applicable to the search of any such building.
19 C.F.R. §123.81