At least 17 people were shot and killed at Marjory Stoneman Douglas High School in south Florida on Wednesday, authorities said.

Police responded to an incident at the school, located in the city of Parkland, around 3:15 p.m. ET. One shooter is believed to have carried out the attack, in the school's freshman building. The suspect, identified as 19-year-old Nikolas Cruz, was taken into custody "without incident," Broward County Sheriff Scott Israel said. The suspect was a former student of the school who had been expelled; one teacher told The Miami Herald that Cruz had been identified last year as "threatening students."

About 3,000 students attend the school, which is described as being in "an affluent Fort Lauderdale suburb," The New York Times writes.

Drone footage of the scene showed handfuls of students fleeing on foot. "My prayers and condolences to the families of the victims of the terrible Florida shooting," President Trump tweeted. "No child, teacher, or anyone else should ever feel unsafe in an American school." The Week Staff

This is a breaking news story and has been updated throughout.

The subpoena wars continue.

House Democrats on Tuesday gathered to to hear testimony concerning Special Counsel Robert Mueller's investigation into 2016 Russian election interference. But, for the second time this month, the witness did not show up. Former White House Counsel Don McGahn followed in the footsteps of Attorney General William Barr, who refused to appear before the House Judiciary Committee earlier in May.

McGahn was directly instructed by the White House to defy a subpoena for his appearance, based on a Justice Department opinion that his former role in the White House means he cannot be compelled to testify about his official duties.

House Judiciary Chair Rep. Jerrold Nadler (D-N.Y.) feels quite differently, however. He made that clear as the hearing, which went on — albeit briefly — even without McGahn. Nadler did acknowledge that McGahn did not "blindly" participate in unethical behavior during Mueller's investigation, but that doesn't mean he's off the hook when it comes to testimony. The congressman tossed aside the White House's stance on McGahn's obligation, arguing that he must show up, and that the Trump administration must cease its meddling in such cases altogether.

Ultimately the debate over whether McGahn must testify will be decided by the courts, Fox News' senior judicial analyst Judge Andrew Napolitano said on Tuesday. "Ultimately, a lot of this will get to the Supreme Court," he said. Tim O'Donnell

One of President Trump's favorite stories just won't stop changing.

As Toronto Star's Daniel Dale reports, Trump has repeatedly recounted an anecdote about a New York City cop apparently thanking him because, as Trump said in December 2017, "My 401(k) is up 39 percent in nine months" and "my family thinks I'm a financial genius."

Trump has continued to tell this story both during rallies and elsewhere, but by the March 2018 telling, the policeman's quote was now, "Sir, thank you very much. My 401(k) is up 41 percent. My wife thinks I'm a genius." In June, it was up to 46 percent. In July, it was back down to 44 percent. And in August, it was back up to 49 percent.

Most recently, Trump during a May 8 rally once again told the story, this time describing the cop as a "big, strong guy" and noting that his supporters "might have heard" this one. Those who have were probably on the edge of their seats wondering what the number would be this time. The answer? 47 percent — down two percent from his August 2018 telling of it.

So what might the percentage be at next? Could it climb past 50 percent? Will it start creeping back down to 39 percent? With plenty of more rallies on the way as Trump prepares to formally launch his 2020 re-election campaign, the suspense is palpable. Brendan Morrow

Bill de Blasio is really counting on winning the "niche music taste" demographic.

The New York City mayor followed more than 20 other people in announcing his 2020 presidential candidacy last week, and has since failed to draw a crowd in any polls — or town halls — out there. Still, de Blasio remains convinced he can win, and he's channeling his punk roots to do it.

In Tuesday morning interview on CNN's New Day, host Alyson Camerota asked, as she apparently does with every candidate, what de Blasio's favorite band is. "My favorite band is the Clash," de Blasio responded before getting wistful about the London Calling album. "Their music spoke about a different, better world," de Blasio said, mentioning Joe Strummer's famous line "the future is unwritten" and saying that applied to "global warming" and "a huge economic inequality" today. De Blasio was also sure to mention that "I love reggae" and, upon prompting from Camerota, "I love ska."

This whole conversation isn't too surprising once you recall what de Blasio looked like in college. Kathryn Krawczyk

Oh, the irony.

President Trump's attorneys have filed an appeal after a federal judge ruled on Monday that Trump could not block a House subpoena of his financial records. The appeal, Politico reports, will be heard by the D.C. Circuit Court of Appeals, which is headed by none other than Merrick Garland (though Garland won't necessarily be on the three-judge panel that will hear the actual appeal.)

Garland was infamously nominated by former President Barack Obama for the Supreme Court in 2016 to replace former Justice Antonin Scalia after his death, but the Republican-controlled Senate refused to to vote on Garland's nomination, claiming Obama's dwindling time in office meant that he should not have the authority to elect a justice who would serve long past the end of his presidency. So instead, lawmakers stalled until after the 2016 presidential election, which resulted in a Trump victory and, subsequently, the appointment of the more conservative Justice Neil Gorsuch.

Now, it's possible the GOP's decision to block Garland could actually serve as a thorn in the president's side — at least in this instance. But it's also likely this won't be the final time Garland will be in the middle of Trump's battles with Congress. Tim O'Donnell

Walmart employees routinely show up at the company's annual shareholders meeting to push for better working conditions. This year, Sen. Bernie Sanders (I-Vt.) is taking their place.

The massive retail chain has been a focus of Sanders' pro-worker push — he even introduced the pointedly titled Stop WALMART Act to Congress last November. Now, the 2020 candidate is arguing that hourly Walmart workers should have a guaranteed seat at the shareholders meeting each year, and he'll make his case right to those shareholders' faces, The Washington Post reports.

Walmart's annual meeting of "a dozen wealthy executives from companies like McDonald's and NBCUniversal" is coming up on June 5 in Bentonville, Arkansas, the Post writes. That's where Sanders will tell shareholders that "if hourly workers at Walmart were well represented on its board, I doubt you would see the CEO of Walmart making over a thousand times more than its average worker," he tells the Post. Walmart pharmacy technician Cat Davis introduced the proposal, which reads that "hourly associates can guide a more fair, inclusive, and equitable corporate ecosystem that bridges differences," and invited Sanders to deliver the message.

Sanders' Stop WALMART Act, introduced in Congress in November, would stop large employers from buying back stock unless they introduced a $15 minimum wage, gave workers 7 days of paid sick leave, and made sure the highest paid employees earn no more than 150 times what the lowest paid are making. Walmart unveiled a revamped paid leave program in February, but Sanders quickly decried it as "not good enough."

Update 11:45 a.m. ET: A Walmart spokesperson issued a statement reading: “We're proud of the fact that 75 percent of our U.S. management associates began their career as frontline hourly associates. If Senator Sanders attends, we hope he will approach his visit not as a campaign stop, but as a constructive opportunity to learn about the many ways we're working to provide increased economic opportunity, mobility and benefits to our associates — as well as our widely recognized leadership on environmental sustainability." Kathryn Krawczyk

Rep. Joaquin Castro (D-Texas) said on Monday night that the Hispanic Caucus — a 38-member congressional caucus chaired by Castro which advocates for issues concerning Latinos in the United States — is turning its focus toward pursuing investigations into the deaths of migrant children in U.S. custody.

The group was stirred to action earlier on Monday after Customs and Border Protection confirmed a 16-year-old Guatemalan boy died while in their custody, though the cause is unknown. It was the fifth death of a migrant child detained by CBP in the last six months, The Hill reports — a fact that Castro called "outrageous and unacceptable."

In a statement, Castro wrote that before the first of the five recent deaths, then-CBP Commissioner and current acting Homeland Security Secretary Kevin McAleenan had said no child had died in CBP custody in more than a decade. But now, Castro said, "it is clear that this Administration's policies hurt families and have proven deadly for immigrant families and have proven deadly for immigrant children and their parents." The Trump administration, he added, "owes the American people answers." Tim O'Donnell