Stay Updated on Developing Stories

What we've learned 3 weeks after the Parkland shooting -- and what's next

(CNN) For the first time since a gunman turned Marjory Stoneman Douglas High School into a scene of carnage, students had their first full day of classes Wednesday.

It's been three weeks since they lost 17 classmates and teachers. In that time, grieving students launched a nationwide movement that could spur new gun laws. Warning signs about the suspect came to light. And gun control legislation gained traction in the state legislature.

While Florida lawmakers passed a bill Wednesday night that includes several gun control measures, a grand jury earlier in the day indicted ex-student Nikolas Cruz on 17 counts of murder.

Here's what we've learned in the aftermath of the shooting, and what's happening next:

The students

What's new: Wednesday marked the first full day of classes at Stoneman Douglas High School in Parkland. NBA star Dwyane Wade stopped by to tell students he was inspired by how they've handled the tragedy.

Many of the students have confronted state and congressional lawmakers, demanding a ban on assault weapons similar to the one used to kill their friends and teachers.

What's next: Stoneman Douglas students say they will continue the fight to ban assault rifles. "I'll definitely be speaking out still until changes are made,' Senior Demitri Hoth said.

On March 14, exactly one month after the gunman killed 17 people at the school, students across the country will walk out for 17 minutes in support of the Stoneman Douglas students.

And on March 24, gun control activists nationwide will participate in the March for Our Lives in Washington. The event was created by Stoneman Douglas students.

A local March for Our Lives in Parkland is also planned for that day. Stoneman Douglas junior Casey Sherman, a coordinator for the local march, said many people want to get involved but may not be able to make it to Washington D.C.

"The march in Parkland is going to be the second largest march next to the one in D.C.," Sherman, 17, said Wednesday after a Parkland City Commission meeting. "Parkland is the center of everything ... we learned here, we grew up together. We go to school here."

The legislation

What's new: Florida House representatives approved a bill that would raise the age for buying firearms to 21; require a three-day waiting period for purchases; and allow some school staff members to be armed on a volunteer basis.

Senate Bill 7026 -- dubbed the "Marjory Stoneman Douglas High School Public Safety Act" -- would also give law enforcement more power to seize weapons and ammunition from those deemed mentally unfit and provide additional funding for mental health services and armed school resource officers.

What's next: The bill now goes to Gov. Rick Scott, who has expressed reservations about the three-day waiting period and the provision that would allow some teachers and staff to carry weapons in schools.

The investigation

What's new: A grand jury indicted Cruz on 34 counts, including 17 counts of premeditated first-degree murder and 17 counts of attempted first-degree murder.

The case involves a complex web of finger-pointing as to who could have helped prevent the massacre, and what signs about suspect Nikolas Cruz were ignored or missed.

Much of the recent blame has fallen on the Broward County Sheriff's Office. One of its armed deputies stayed outside the school as the massacre unfolded. And in the past decade, authorities received more than 20 calls about Cruz and his family.

Sheriff says he got 23 calls about shooter's family, but records show more

The sheriff's office recently launched a website "setting the record straight." It says while deputies did respond to Cruz's home multiple times in the past, there was nothing criminal nor dangerous happening that would warrant an arrest.

What's next: More details may be released now that the grand jury has finished its deliberation.

On Wednesday night, Parkland residents will have a chance to grill local officials and authorities at a city commission meeting.

The school district's response

What's new: The Broward County school board passed a 24-point resolution Tuesday, calling for Congress to ban assault weapons, require universal background checks and broaden the perimeters of school gun-free zones.

The proclamation also slammed the idea of arming teachers -- the topic most heavily debated this week in the state legislature.

What's next: Superintendent Robert Runcie said he wants an immediate, independent review of the social and educational history of Nikolas Cruz.

While the school district took steps to try to prevent such carnage in the future, a student who was shot five times plans to sue the school district, Broward County, and the Broward County Sheriff's Office.

The suspect

What's new: We now know that last year, someone using the name "nikolas cruz" posted a chilling comment on YouTube: "im going to be a professional school shooter." The FBI was warned, but didn't notify local law enforcement.

Others who knew Cruz growing up described him as deeply disturbed, saying he tormented animals, threw rocks at cars, and sometimes introduced himself by saying, "I'm a school shooter."

What's next: Cruz remains in the Broward County Jail, where he's been segregated from the other inmates.

CNN's Rosa Flores, Chuck Johnston, Kevin Conlon, Dakin Andone and Ray Sanchez contributed to this report.
Outbrain