A Grass Valley man arrested for allegedly arranging to have sex with underage girls has pleaded no contest to three charges in return for a possible sentence of three years. Samuel Joseph Luti, 20 at the time, was arrested at a local motel Sept. 28, 2011, where he allegedly had arranged to have sex with a 15-year-old. Grass Valley Police learned Luti allegedly had been texting and going online to communicate with girls ranging in age from 12 to 15 to solicit sex acts, sending them photos of inappropriate male body parts. Luti also allegedly was using marijuana to solicit …