A plea hearing is set for October 23rd in Waupaca County Circuit Court for one of three men charged in the death of an Illinois man from a pipe bomb explosion. The plea and sentencing hearing is for 43 year old Kenneth Niemer of Clintonville. Niemer, along with 60 year old Scott Mattes of Marion and 37 year old Robert Mattes of New London each face a count of homicide by negligent handling of a dangerous weapon. The three, along with 44 year old Paul Casperson of Bellvidere, Illinois, were allegedly lighting off a pipe bomb in a field at E 6300 County Highway “S” in late May. The criminal complaint says when the first attempt to explode the pipe failed, paper towels and a can of WD-40 were stuffed down the pipe. The second time the pipe did explode, with steel fragments hitting Casperson in the abdomen. He died from his injuries. The three charged in the case are free on 25-thousand dollar signature bonds.