Speaking at the White House, President Obama called for unity after the killing of police officers in Baton Rouge, La. on Sunday. Yuri Gripas/AFP/Getty Images hide caption

toggle caption
Yuri Gripas/AFP/Getty Images

French fire brigade members aid an injured individual near the Bataclan concert hall following fatal shootings in Paris. Christian Hartman/Reuters/Landov hide caption

toggle caption
Christian Hartman/Reuters/Landov

Police investigate the scene of a shooting at 75th Street and Stewart Avenue on Saturday in Chicago. At least 50 people were shot in the city, nine of them fatally, in a wave of violence over the Fourth of July weekend. E. Jason Wambsgans/MCT /Landov hide caption

toggle caption
E. Jason Wambsgans/MCT /Landov

Mindy Corporon speaks during a news conference, flanked by Will Corporon (left) and Tony Corporon, at their church in Leawood, Kan., on Monday. Their father, Dr. William Corporon, and Mindy Corporon's 14-year-old son were killed during Sunday's shooting at the Jewish Community Center in Overland Park, Kan. Orlin Wagner/AP hide caption

toggle caption
Orlin Wagner/AP

Frazier Glenn Cross, also known as Glenn Miller, is accused of killing three people Sunday in Kansas City. He allegedly attacked them at a Jewish community center and a Jewish retirement facility. Johnson County, Kan., Sheriff's Office hide caption

toggle caption
Johnson County, Kan., Sheriff's Office

Bob Butler (left) and Bob Gordon paint crosses they placed in front of American flags at Central Christian Disciples of Christ church in the city of Killeen, Texas, which is home to Fort Hood. Joe Raedle/Getty Images hide caption

toggle caption
Joe Raedle/Getty Images

Sgt. First Class Erick Rodriguez stood guard at the entrance to Fort Hood as officials prepared to brief the news media about Wednesday's attack at the post. Erich Schlegel /Reuters/Landov hide caption

toggle caption
Erich Schlegel /Reuters/Landov