Florida’s U.S. senators described the horrific scene at a Parkland high school on Wednesday where a shooter opened fire on students, killing at least 17 people. “He wore a gas mask and smoke grenades. He set off the fire alarms so the kids would come out in the hallways. And thus, he had the opportunity with the crowded hallways to start picking off people,” Sen. Bill Nelson (D-FL) said on MSNBC. Sen. Marco Rubio (R-FL) said on Twitter that he was briefed on the attack, which was “designed & executed to maximize loss of life.” The alleged shooter, Nikolas de Jesus Cruz, is in custody.