The U.S. flag flies at half-staff May 15, 2015 at Joint Base Charleston, S.C., during a police week retreat ceremony to honor servicemembers who made the ultimate sacrifice. The week is celebrated nationally to remember those who have been killed in the line of duty. (U.S. Air Force photo/Senior Airman Jared Trimarchi)

A police officer and member of the 628th Security Forces Squadron stands in formation May 15, 2015 at Joint Base Charleston, S.C., during a police week retreat ceremony. The week is celebrated nationally to remember those who have been killed in the line of duty. (U.S. Air Force photo/Senior Airman Jared Trimarchi)

Retired Col. Lawrence Lane, the first Phoenix Raven, salutes Staff Sgt. Chris Moore, the newest 628th Security Forces Squadron Raven, May 15, 2015 at Joint Base Charleston, S.C., during a police week retreat ceremony. Ravens are security forces members who are extensively trained to provide security for Air Mobility Command aircraft transiting through high threat areas. The week is celebrated nationally to remember those who have been killed in the line of duty. (U.S. Air Force photo/Senior Airman Jared Trimarchi)

Capt. Jon Blount, 628th Security Forces Squadron, salutes the flag May 15, 2015 at Joint Base Charleston, S.C., during a police week retreat ceremony. The week is celebrated nationally to remember those who have been killed in the line of duty. (U.S. Air Force photo/Senior Airman Jared Trimarchi)

Sailors applaud guest speaker (Ret.) Col. Lawrence Lane, the first Phoenix Raven, May 15, 2015 at Joint Base Charleston, S.C., during a police week retreat ceremony. Ravens are security forces members who are extensively trained to provide security for Air Mobility Command aircraft transiting through high threat areas. The week is celebrated nationally to remember those who have been killed in the line of duty. (U.S. Air Force photo/Senior Airman Jared Trimarchi)

Defenders from the 628th Security Forces Squadron salute May 15, 2015 at Joint Base Charleston, S.C., during a police week retreat ceremony. The week is celebrated nationally to remember those who have been killed in the line of duty. (U.S. Air Force photo/Senior Airman Jared Trimarchi)

Defenders from the 628th Security Forces Squadron lower the flag May 15, 2015 at Joint Base Charleston, S.C., during a police week retreat ceremony. The week is celebrated nationally to remember those who have been killed in the line of duty. (U.S. Air Force photo/Senior Airman Jared Trimarchi)