Three Baton Rouge police officers were killed Sunday after being ambushed and shot by a lone shooter in Baton Rouge, Louisiana. The officers, Montrell Jackson, Matthew Gerald, and Brad Garafola, were killed in the same city where the death of Alton Sterling at the hands of police sparked a tumultuous national response for two weeks. On Sunday, Baton Rouge police were responding to a phone call about “suspicious person walking down Airline Highway with an assault rifle,” a source with knowledge of the investigation told CNN. Once police arrived, the shooting began. The shooter, Gavin Long, was shot and killed by police responding to the scene. Law enforcement officials said his weapon of choice was an AR-15 style semi-automatic rifle. “We as a nation have to be loud and clear that nothing justifies violence against law enforcement,” President Barack Obama said after Sunday’s attack. “Attacks on police are an attack on all of us, and the rule of law that makes society possible.” This being the second ambush on police officers in the past week, police across the nation are taking safety precautions.