AMNA NAWAZ: Good evening, and welcome.

Authorities are still searching for a motive in the shooting at a Christian elementary school in Nashville, Tennessee, that left six people dead.

GEOFF BENNETT: Law enforcement said today the shooter bought seven guns legally, three of which were used in the murders.

And Nashville police released new video of their response.

Stephanie Sy has the latest.

And a warning: Her report includes video that some viewers may find upsetting.

STEPHANIE SY: Newly released surveillance video shows the shooter driving up to the Covenant School, and gaining entry into the building by shooting through a side door.

It is 10:10 a.m.

The suspect walks through the halls carrying two assault-style rifles and a handgun.

Police received reports of the shooting three minutes after entry, around 10:13.

As police officers arrive at the scene, the assailant fires at their vehicles.

MAN: I'm making entry on the front side.

STEPHANIE SY: Body camera footage shows officers following the sound of gunshots to the second floor, where they confront and kill Audrey Hale.

Hale was a former student at the Christian school.

Police have obtained writings and campus maps they say show hale calculated the attack.

They also say Hale had other targets in mind.

Police have given unclear and sometimes conflicting information about Hale's gender.

But they said today the guns used by the shooter were legally obtained.

Police Chief John Drake said investigators are in contact with Hale's parents.

JOHN DRAKE, Metro Nashville Police Chief: We know that they felt that she had one weapon, and that she sold it.

She was under care, a doctor's care, for an emotional disorder.

Law enforcement knew nothing about the treatment she was receiving.

But her parents felt that she should not own weapons.

They were under the impression that, when she sold the one weapon, that she did not own anymore.

As it turned out, she had been hiding several weapons within the house.

STEPHANIE SY: In Nashville, mourners continued to gather at the elementary school today to lay flowers and pay their respects.

KAYLEE FRANZEN, Nashville: It sends a message that things need to change and that thoughts and prayers alone aren't something that fixes or can aid this situation.

STEPHANIE SY: The student victims were Evelyn Dieckhaus, Hallie Scruggs, and William Kinney, all 9 years old.

The three adults killed included the head of the school, Katherine Koonce.

Cynthia Peak was a substitute teacher, Mike Hill a custodian.

As voices rise for lawmakers in Washington, D.C., to do something about the epidemic of gun violence, this morning, the Senate chaplain's morning prayer was a call for divine intervention.

BARRY BLACK, Senate Chaplain: Lord, when babies die at a church school, it is time for us to move beyond thoughts and prayers.

Remind our lawmakers of the words of the British statesman Edmund Burke: "All that is necessary for evil to triumph is for good people to do nothing."

STEPHANIE SY: A prayer, as much as a call for action in the growing chorus of grief.

For the "PBS NewsHour," I'm Stephanie Sy.

GEOFF BENNETT: Amid the shock of the tragedy in Tennessee are renewed calls for leaders and lawmakers to do something.

Kris Brown is president of Brady, a gun reform advocacy group, and joins us for more on what that something could be.

Thank you for being with us.

KRIS BROWN, President, Brady Campaign to Prevent Gun Violence: Thank you for having me.

GEOFF BENNETT: The assailant, as we heard in that report, legally purchased seven firearms, three of which were used in the murders, according to Nashville police, as this person was being treated for an emotional disorder.

This person's parents didn't know that the guns were in the house.

How do we solve for that?

What piece of legislation, what policy would have prevented this from happening?

KRIS BROWN: Extreme risk protection laws.

Actually, 19 states and the District of Columbia have passed those last year.

President Biden sign the bipartisan Safer Communities Act to give funding to states and to incent other states to pass these laws.

Why is that relevant?

Because what that says is, as a law, if you have someone in your household who's at risk of doing themselves harm or others, you can seek a protective order from the court to remove all firearms.

And, in some states, that also means that person is put into the background checks system.

So we need that kind of law.

Tennessee does not have that law.

So, when I hear what the parents are saying, it breaks my heart.

I think they tried and did what they could.

But Tennessee does not offer them other solutions that they should.

And they must, because this is far too frequent in our life today.

And we need all of the tools that we can amass to stop gun violence.

GEOFF BENNETT: And, at the federal level, the gun reform debate appears to be frozen.

President Biden today said that Congress needs to act.

He said he's exhausted the range of what he can do unilaterally.

But there are a couple of things I want to point out that suggest that Congress won't act on this anytime soon.

One is Congressman Andy Ogles, whose district includes that Christian school.

He received widespread criticism from gun control advocates for a Christmas photo that he posted in 2021 of his family, you see there, posing with AR-style rifles.

Today, he said that he has nothing to apologize for, didn't see anything wrong with that.

And then there's Tennessee Congressman Tim Burchett, who talked to reporters yesterday, and said, there's no way to fix gun violence.

REP. TIM BURCHETT (R-TN): I don't see any real role that we could do, other than mess things up, honestly, because of the situation.

It's -- like I said, I don't think a criminal is going to stop from guns.

You can print them out on the computer now, 3-D printing.

And there's really -- I don't think you're going to stop the gun violence.

I think you have got to change people's hearts.

GEOFF BENNETT: Is that where the public sentiment is, that there's no role for Congress, Congress can only mess things up?

KRIS BROWN: No.

It's a failure of democracy.

What we're hearing here is manifestly against what every poll tells us the American people want; 93 percent of Americans want expanded background checks.

Why is that?

Because they know that background checks save lives.

We have stopped more than four million, through the Brady law, four million sales of guns to prohibited purchasers.

But, today, one in five guns is sold with no background check at all.

Why is that?

Over the Internet and at gun shows, these guns can be sold with no background check by private sellers, because when Jim and Sarah Brady passed the law, there was no Internet, and there were no gun shows.

And there are so many other things that we can do.

President Biden has talked about some of them.

For those who say, we can't do anything, let's look at the kinds of things that they're actually doing in Congress and in state legislatures to reverse, to back-roll the kinds of public safety that are important to us.

Just today, Congress was supposed to have a hearing in the House about certain kinds of devices that can be added to assault-style weapons to make them more deadly.

They canceled that hearing.

Why?

Because of this shooting, because there are certain reports that indicate that the shooter used those kinds of devices.

Brace stabilizers is what they're called.

Obviously, people like him who talk about, we can't do anything, they're the ones who are trying to roll back protections.

And I have to say the issue that we as Americans should really internalize is, do we want a version of the Second Amendment that is a death sentence to our fellow Americans?

Are we going to make this a key political issue, or won't we?

Because we have to hold people like that lawmaker and others to account.

They have blood on their hands.

I can't vote.

I wish I could.

I can't vote in Congress, but I can vote at the ballot box.

And every time I do, I make gun violence prevention a priority.

And that's what we must do if we want to change the trajectory of our country.

This is a national shame.

We cannot say we live in a country, the land of the free, the home of the brave, when our kids are dying at school and when gun violence is the number one killer of our children, surpassing automobile fatalities.

We have to make a difference, and we can.

We can.

And we should.

We're Americans.

GEOFF BENNETT: Kris Brown, president of Brady, thank you for your insights and thanks for being with us.

KRIS BROWN: Thank you.