PRINCETON – A Spring Valley man accused of killing his girlfriend has pleaded not guilty at the Bureau County Courthouse on Monday. 37-year-old Eddie L. Mentgen is charged with first degree murder for his alleged involvement in the April 5th homicide of Marissa Roberts. 28-year-old Roberts of Spring Valley was found dead in her apartment on Ponsetti Drive. It was reported that Mentgen fled to Wisconsin after the incident. He will remain in the Department of Corrections until pretrial on August 19th at 9 a.m. His trial is scheduled for September 9th at 9 a.m., tentatively. Bureau County State’s Attorney Geno Caffarini says his plea was expected. If Mentgen is found guilty he faces a minimum of 20 years in jail to a maximum of 60 years with no probation.