A Syracuse man serving 40-70 years for killing his girlfriend has appealed his conviction and sentence.

An attorney for Ronald Smith filed the appeal in Otoe District County Court, but didn't explain in court documents why the conviction should be thrown out.

Smith was found guilty in September of second-degree murder in the death of 51-year-old Terri Harris.

Harris was found dead Dec. 25 in her Syracuse home. Smith confessed to pushing her to the floor in her bedroom and placing a pillow over her head until she suffocated.

Law enforcement found Smith in Illinois after he had forged checks in Harris' name at a Syracuse bank. He also had stolen Harris' car and cell phone.