A northeast Iowa man has been found guilty of first-degree murder.A Grundy County jury returned the verdict Tuesday afternoon in the trial of 38-year-old Lynn LaMasters of Jesup. The prosecution successfully argued that LaMasters strangled his live-in girlfriend, Patricia Rapacki, in December of 2003, then placed her body in a basement freezer inside their home. Authorities found Rapacki’s body on January 12th, 2004, days after LaMasters was arrested for leading police on a high-speed chase with the victim’s car. Jurors deliberated about four hours before returning their verdict. The trial, which began March 17th, took place in Grundy Center on a change of venue. LaMasters now faces a sentence of life in prison. The sentencing date hasn’t been set.