BATON ROUGE, La. — A lone gunman killed three police officers and wounded three others after opening fire at a convenience store in Baton Rouge, Louisiana, Sunday. The shooter has been identified as Gavin Eugene Long, a black male from Kansas City, Missouri, who just a handful of years ago was a Dean’s List student at the University of Alabama.

Long was killed on site by police who responded to calls for help.

According to police radio transmissions, which can be heard below, a woman first called 911 reporting a suspicious man walking along the road with an “assault rifle.” Just moments later, an officer can be heard yelling over the radio, “Shots fired, officer down! Shots fired, officer down!” Another officer then says, “We do not have a 20 on the shooter; he is not in sight… Officer sniper!”

Within minutes of backup arriving, the shooter was dead.

The vicious attack, which the Baton Rouge mayor referred to as “an ambush,” comes after several days of protests in the city over the death of Alton Sterling, a local man who was killed after an altercation with police on July 5. The investigation into his death is ongoing.

Very little additional information about Gavin Eugene Long is known at this time. Court records show he was divorced in 2011 and the University of Alabama’s website shows him as a Dean’s List student in 2012.

Alabama Governor Robert Bentley released the following statement in response to the shooting:

Once again we are troubled and heartbroken to hear of yet another act of senseless violence in our nation. Alabama joins the nation in praying for the men and women in law enforcement who willingly put themselves in harm’s way to protect all of us. Our nation must find our way to unity once again, even in the midst of so much division, violence and anger. We cannot rely on any one person to fix what is broken. We, the people are all a part of one nation under God, where there is liberty and justice for all.