We live in Milwaukee, Wisconsin. My neighbor has applied for and received a permit to build a fence 4 inches from his and mine property line. He believes that his property is wider by 6 inches and is building his fence six inches into my property that is surveyed and staked by 3 foot long pipes. He agrees with one of the 3 foot pipes and not the other. We have shown him where the property line is but he disagrees. We have had our municipality send him a letter that the fence permit states that the entire structure of the fence must be on his own property. He replied to the municipality that he is within his bounds of his own property which he believes is 6 inches beyond the stakes and is continuing to instruct his contractor to construct his fence.