An 18-year-old man accused of fatally shooting a San Francisco teen in order to steal a gun the boy was trying to sell pleaded not guilty to murder today. Robert Griffin, who was arrested in San Francisco on Friday, was arraigned at a brief hearing in San Francisco Superior Court this morning on charges of murder, robbery and burglary for the killing of 17-year-old William “Nicky” Huertas on June 12. Members of Huertas’ family looked on tearfully as Griffin pleaded not guilty to the charges. He remains in custody on $2 million bail and is due back in court Aug. 18. According to police and prosecutors, Huertas had been trying to sell the .22-caliber rifle, a family heirloom, and invited Griffin to the home in the 1100 block of Turk Street in the city’s Western Addition neighborhood to inspect the weapon. Once inside, however, police said Griffin shot Huertas once in the head and made off with the rifle. It was recovered three days after the killing. Griffin is believed to have family in Oakland but had no fixed address at the time, according to police. Prosecutors have said two witnesses identified Griffin as the suspect. Additionally, prosecutors said, there is video evidence of Griffin and another man getting rid of the stolen rifle. Griffin’s newly appointed attorney Steven Gayle said he had just begun receiving evidence in the case and could not comment this morning.