ST. PAUL, Minn. (AP) – The black mayor of St. Paul, Minnesota, has received racist threats amid a long-simmering dispute over how the city should collect its trash.

Police in Minnesota’s capital city are investigating threatening and racist messages to Mayor Melvin Carter in the run-up to a citywide vote on organized trash collection.

Carter is St. Paul’s first African American mayor. He has warned the city could face hefty property tax hikes if voters reject the trash ordinance on Nov. 5.