Stoneman Douglas students return to school after mass shooting

Students were greeted by supporters, signs and flowers as they returned to class at Marjory Stoneman Douglas High School on Feb. 28, 2018, in Parkland, Fla.

Law enforcement agents line up as students head back to school at Marjory Stoneman Douglas High School on Feb. 28, 2018, in Parkland, Fla.

Law enforcement agents and parents stand by as students head back to school at Marjory Stoneman Douglas High School on Feb. 28, 2018 in Parkland, Fla.

Police pose for a photo after they escorted returning students to Marjory Stoneman Douglas High School in Parkland, Fla., on Feb. 28, 2018.

A returning student reacts as he walks to Marjory Stoneman Douglas High School in Parkland, Fla., on Feb. 28, 2018.

Students are greeted by law enforcement as they head back to school at Marjory Stoneman Douglas High School on Feb. 28, 2018, in Parkland, Fla.

Students are greeted by law enforcement as they head back to school at Marjory Stoneman Douglas High School on Feb. 28, 2018, in Parkland, Fla

Students are greeted by law enforcement as they head back to school at Marjory Stoneman Douglas High School on Feb. 28, 2018, in Parkland, Fla.

Camille Aponte walks with her son Nelson Laboy as he heads into school at Marjory Stoneman Douglas High School amid heavy security for the first time after a former student opened fire at the school in Parkland, Fla., on Feb. 28, 2018.

A student walks to Marjory Stoneman Douglas High School in Parkland, Fla., on Feb. 28, 2018.

Marjory Stoneman Douglas High School student David Hogg, left, walks to class for the first time since a former student opened fire there with an assault weapon, on Feb. 28, 2018, in Parkland, Fla.

Students walk to class at Marjory Stoneman Douglas High School in Parkland, Fla., on Feb. 28, 2018.