The question remains of whether the Oct. 10 school shootings in Ohio could have been prevented.
Authorities are re-tracing the long and troubled trail the teenage gunman left behind him.
Cleveland police investigating the shooting made an arrest on Oct. 11.
They took shooter Asa Coon's 18-year-old brother into custody, though it's not known why.
Police are also releasing new information about Coon's violent past. They'd been to his home on several calls, including domestic violence and assault.
"Since 2006, we responded to the shooter's residence five times," Chief Michael McGrath assured, with the Cleveland Police Dept.
Parents still want to know how Coons got into the school with the weapons.
Why wasn't there a metal detector? And why didn't the security guard stop him?
One student says she warned the principal last week that Coons was making threats.
"Ever since Columbine, what we've learned in most school shootings is that somebody always knew something," security expert Ken Trump said.
School officials say in light of the shooting, they'll have a new safety plan drawn up by Oct. 12.
"The safety and security side will address what type of devices are used to protect students in our school, as well as what other security measures are put in place, securing entrance into school," said Maureen Harper, Cleveland city spokeswoman.
If there's one glimmer of good news a day later, it's the prognosis of the two students and two teachers shot.
They're all recovering. Only one will still be in the hospital after Oct. 11.
David Kachadourian was among those shot.
"I was teaching class and I heard a loud popping noise and didn't think anything about it. It didn't seem like what I would imagine a gunshot to sound like," Kachadourian admitted.
Another violent school rampage may have been prevented.
Authorities in the Philadelphia area say a teenager was taken into custody after police found weapons in his bedroom.
Police also say the teen had tried to recruit another boy for a possible attack at a high school.
The teen is being charged as a juvenile with solicitation to commit terror and other counts.