An arraignment has been scheduled for later this month for a man accused of killing Sac City resident Mark Koster. Trial information was filed on Monday in the case of 54 year-old John Green, who authorities say killed Koster in 2009 and hid his remains in Koster's Sac City home. He is facing a charge of first-degree murder and will be arraigned on April 21. Green was arrested in Florida on March 24 and was returned to Iowa five days later. Authorities have said Green admitted to killing Koster. He remains held without bond in the Sac County Jail.