The Sac City Police Department released new information Wednesday that the bones had been found buried in the floor of the basement.
Koster was reported missing in 2009 and was legally declared dead in 2011. Authorities obtained a warrant and searched the home in 2009. They did not find the body and reported at the time that there were no signs of foul play. It was assumed that Koster had left the home. Eventually, as bills piled up at the vacant house, utilities were shut off and it stood empty until sold to a new owner in May.
With police terming the location of the body as "suspicious circumstances," the investigation will continue.
An unknown male had reportedly been staying with Koster for about three months before he went missing. Anyone with information - especially on the identity of Koster's roommate - is being urged to contact Sac City Police at 712-662-7772.