A 16-year-old boy was arrested Saturday on suspicion of murder after his grandparents were found dead at their home in central Japan, police said.The high school student in Tahara, Aichi Prefecture, is suspected of fatally stabbing his 75-year-old grandfather around 2 a.m. Friday, the prefectural police said. His 72-year-old grandmother was also found dead in the house where the three lived with two other family members, according to the police.The boy has admitted to killing his grandfather with a knife, the police said, adding he also indicated his involvement of killing of his grandmothe…READ FULL ARTICLE