David Hogg, a survivor of the school shooting in Parkland, Florida, said Monday that the school shooting in Madison, Wisconsin, shows “we still haven’t done enough” to stop gun violence against children.

“We still have a lot to do. “Obviously Congress needs to do more to combat these things and prevent them in the first place,” he told ABC News on Monday.

“At the same time, I’m also thinking about the shootings that we don’t hear about because they were prevented by the Red Flag law that we passed after Parkland.”

The family of Madison school shooter Natalie Rupnow is cooperating with police, Madison officials said Monday night.

The 15-year-old’s father spoke to police Monday evening, Madison Police Chief Shon Barnes told reporters.

“We have no reason to believe at this time that they have committed a crime,” Barnes said of the family.

The Madison Police Department has responded to rapidly spreading, unconfirmed online speculation that the shooter in today’s Madison school shooting was transgender.

Chief Shon Barnes said Monday night that he did not know whether Natalie Rupnow, who died in the shooting, was transgender, but that gender was not immediately important.

“I don’t think what happened today had anything to do with how she, he or they wanted to identify,” Barnes said. “I wish people would leave their personal biases aside. We have people doing another school shooting in Madison. That’s what I’m going to focus on in the near future.”

According to police, it was a second-grader who called police Monday morning to alert them to the shooting in Madison.

“Let this sink in for a moment: A second grader called 911 at 10:57 a.m. to report a school shooting,” Madison Police Chief Shon Barnes said Monday.

The shooting occurred in a study hall filled with students from different grades, police said.

Madison police have identified the gunman who killed two people and died in a school shooting Monday morning.

The person is 15-year-old Natalie Rupnow, who was previously described by officers as a student at the school.

Police said Monday that a suspected document from the shooter circulating online had not been verified.

Law enforcement authorities believe the gunman who killed two people and died in a school shooting in Madison, Wisconsin, on Monday planned the attack in advance.

The person detailed personal issues and expressed some of that information in writing, an unnamed law enforcement source told CNN.

So far, police have not publicly discussed a motive, target or pre-conceived plan for the attack.

Police don’t know if the shooting had a specific target or motive.

“Whether they were targeted or not would affect motivation, and we don’t know the answer yet,” Madison Police Chief Shon Barnes said Monday.

School officials are still discussing whether students will return to classes at Abundant Life Christian School this week after a mass shooting left three dead and six injured on Monday. “Whether we return to class this week — because that was our last week, we finished on Friday — is still a decision to be made,” Barbara Wiers, director of elementary and school relations for Abundant Life, told The Associated Press.