A Tenants Harbor man charged with killing his drug supplier for cutting him off has pleaded not guilty. Andrew Kierstead was arraigned Wednesday in Knox County Superior Court on a murder charge in connection with the Sept. 27 shooting of Richard Mills outside his Cushing home. Kierstead remains behind bars without bail. The judge also denied the prosecution’s request for a forensic evaluation of Kierstead to determine his state of mind at the time of the shooting following objections from the defense. Police say Kierstead told them he fired a shotgun repeatedly at Mills because the victim had hooked him on drugs and had been supplying him for 10 or 15 years, but then shut him off for not paying a drug debt.