Police in Baton Rouge have arrested a 12-year-old boy they say was involved in a plot to shoot police officers. Three others had been arrested a day earlier: a 13-year-old boy, a 17-year-old, and a 20-year-old. The group was allegedly planning to kill police using stolen handguns. The incident comes at a time when tensions are high in Baton Rouge after the July 5 police shooting of Alton Sterling, which prompted protests across the nation. The shooting triggered a major backlash against police, who many believe wrongfully killed Sterling even though he was cooperating. Five police officers were killed in Dallas at a Black Lives Matter protest over the shooting on July 7.