Police are investigating a case of arson in Milford Township after responding Friday evening to a structure fire on County Road 29. The structure was a vacant residence in the 17000 block of County Road 29 in New Ulm. The fire department was dispatched to the blaze around 6:40 p.m. Authorities are asking anyone who may have witnessed suspicious activity in the area to contact the Brown County Sheriff’s Office at 507-233-6720 or via email at tipsline@co.brown.mn.us.