A man accused of first degree murder in the 2009 death of a Sac City man has pleaded not guilty. 54 year-old John Green entered the written plea through his Fort Dodge-based attorney Charles Kenville. Green is facing the charge in connection to the death of 58 year-old Mark Koster. Authorities say Koster was killed in 2009 and his remains turned up in the basement of his Sac City home in November of 2012. Green was arrested in Florida on March 24. A trial date has not been set.