"Putting out a tweet like this, full of your BS on a day when 3 children died is disgusting @senatemajldr," Fred Guttenberg wrote.
"Wanna hear what is oppressed? My shot gun ammo because I am wasting it on minorities like you," the student wrote, according to police.
The final report from the Trump administration's Federal Commission on School Safety makes numerous recommendations. None involve gun control.
Parents of Parkland school shooting victims are rallying behind Senator Bill Nelson as he seeks re-election.
Transcript of police interview that took place hours after school shooting is released by authorities.
The Broward Sheriff's Office said the suspect took money from the cash register and left before returning and shooting Ayub Ali.
Children under five were also taught to stay quiet "for a whole minute."
"We always was watching him. He was one of those kids you always kept an eye on."
Campaign groups identify 10 states where pro-gun lawmakers could be forced out.
Thousands of teachers used #ArmMeWith on social media with requests ranging from "politicians who care more about kids than donations" to "smaller class sizes so that no student feels invisible."