CALEDONIA, Minn. (AP) — An independent investigation has found a southeast Minnesota zoning official used his power to retaliate against people who opposed silica sand mining.

The Star Tribune reports the investigation's findings on Bob Scanlan led to a three-day suspension as well as mandatory ethics training. Scanlan is the Houston County zoning and planning director.

The investigation says Scanlan targeted people who spoke out against sand mining at public meetings or in letters to the Houston County Board, handing down false zoning violations and threatening to tear down one person's house.

The Houston County Board recently deadlocked over a proposed ban on the practice. A three-year moratorium recently expired.

Scanlan declined to comment to the Star Tribune.