SHEBOYGAN, Wis. (WHBL) - A former Sheboygan man will be doing more time in prison for threatening Sheboygan County judges after losing his appeal of a conviction two years ago. 33 year old Wallace Martonez had been sentenced to prison by Judge Timothy Van Akkeren for a sexual assault conviction. He was found guilty by a Sheboygan County jury of sending threatening letters from his prison cell and sentenced to 4 additional years. Martonez had appealed on grounds that evidence in the case was insufficient despite testimony from a fellow inmate who said Martonez had paid him to write the letters. The Court of Appeals handed down its decision today, rejecting the appeal. Martonez was nearing completion of his three year term when the letters were sent.