FBI agents and other law enforcement officers investigate the scene of Thursday night's shooting.

Notes, flowers and other items decorate a squad car at a make-shift memorial in front of the Dallas police department on Saturday.

Dallas police officer D. Webb gets a hug after a prayer service Friday in downtown Dallas after the shootings during a peaceful protest on Thursday that left five police officers dead.

A Dallas Area Rapid Transit car and a Dallas police cruiser sit in front of Dallas police headquarters Friday, serving as a makeshift memorial honoring the officers killed Thursday night.

Vicente Alfaro lays his hands on a police cruiser Frida outside police headquarters in Dallas. Alfaro and other family members said they came from Irving, Texas, to pay their respects to the fallen officers. "We really have a lot of respect for the people who protect us," he said. "So many people don't really thank them enough."

Adela Greer puts a card on a Dallas police cruiser that was part of a memorial Friday outside police headquarters.

Noelle Hendrix places flowers near the scene of a shooting where five police officers were killed the previous evening in downtown Dallas, on Friday.

A Dallas police officer, who did not want to be identified, takes a moment as she guards an intersection early Friday morning.

A Dallas police officer covers his face as he stands with others outside the emergency room at Baylor University Medical Center.

A clerk looks at broken windows that were shot out at a store in downtown Dallas.

Dallas Police Chief David Brown, front, and Dallas mayor Mike Rawlings, rear, talk with the media during a news conference on Friday.

A Dallas Area Rapid Transit police officer receives comfort at the Baylor University Hospital emergency room entrance on Thursday night.

Dallas Police respond after shots were fired at a Black Lives Matter rally in downtown Dallas on Thursday.

Dallas police respond after shots were fired at a protest in downtown Dallas on Thursday night over the killing of Alton Sterling by police officers in Baton Rouge, La., and Philando Castile, who was killed by police less than 48 hours later in Minnesota.

Police respond after shots were fired Thursday night in downtown Dallas. Three officers died and three others were critically injured.

Police move to detain a driver after snipers shot 11 police officers in downtown Dallas.

An officer stands watch after the shooting in downtown Dallas.

Police and others gather at the emergency entrance to Baylor Medical Center in Dallas, where several police officers were taken after the shootings.

Law enforcement personnel walk near evidence markers at the scene of the police shootings in Dallas.

An FBI agent stands by three damaged Dallas police cruisers at the intersection of Lamar and Main.

Chris Bailey walks by a makeshift memorial on Griffin Street holding a sign that reads, "Everybody Love Everybody" on Friday.