Tennessee stopped the planned execution of death row inmate Tony Carruthers after medical staff could not secure the intravenous access needed to carry it out, officials said. Carruthers, 57, had been set to die by lethal injection at a Nashville prison for the 1994 killings of Delois Anderson, her son Marcellos Anderson and Frederick Tucker. According to the Tennessee Department of Corrections, medical personnel successfully placed a primary IV line for the lethal drugs but were unable to locate a suitable vein for the…