BOONE, Iowa (AP) — A Georgia man has been found guilty of second-degree murder in the killing of his former roommate in 2009. Jurors deliberated for about four and a half hours before returning a guilty verdict Friday to 55-year-old John Green. He was charged with first-degree murder in the death of 58-year-old Mark Koster, of Sac City, but convicted of the lesser offense of second-degree murder.

Defense attorneys say Green killed Koster in self-defense. But prosecutors argue that Green significantly outweighed Koster and therefore didn’t need to kill the man to defend himself.

Koster was declared missing in 2010. His remains were later found buried in his basement after new owners began renovations.

Green’s second trial in the case began Monday. The first ended in a mistrial.