 Chafin 's conflict with the unions became most pronounced during the Battle of Blair Mountain in August and September 1921 . A strike , with its beginning in 1920 , had led to increasing violence throughout southern West Virginia , including the Battle of Matewan . The growing violence led to a declaration of martial law in 1921 , and a Congressional investigation into the circumstances in the area began , but it accomplished little . Then Sid Hatfield , the miners ' hero from the Battle of Matewan , was killed on August 1 by Baldwin @-@ Felts agents on the steps of the McDowell County Courthouse in Welch . After his murder and funeral , tensions erupted in southern West Virginia . 
