South Korea's Chosun Ilbo newspaper reported that North Korean leader Kim Jong Un executed lead nuclear negotiator Kim Hyok Chol and four other senior foreign ministry officials in March, in punishment for the failure of February's Hanoi summit with President Trump. South Korea's government and acting U.S. Defense Secretary Patrick Shanahan said they can't or won't confirm the report, which Chosun Ilbo attributed to one unidentified source, but North Korea's official Rodong Sinmun newspaper also published an editorial Thursday with specific language it last used after a top official was executed in 2013.

The rumors of a post-summit purge aren't new. ABC News This Week's Jonathan Karl asked Secretary of State Mike Pompeo about the rumored executions on May 5. Pompeo didn't confirm or deny them. "It does appear that the next time we have serious conversations that my counterpart will be someone else, but we don't know that for sure," he said, smiling. "Just as President Trump gets to decide who his negotiators will be, Chairman Kim will get to make his own decisions about who he asks to have these conversations."

It's not clear if the firing squad reports are true, and if so, whether the U.S. knew that three weeks ago. But if Pompeo knew, his response and body language are a little unsettling. "Secretary Pompeo in all likelihood knew when he answered this question that Kim Jong Un had executed and imprisoned his interlocutors," tweeted Ned Price, a former CIA officer and National Security Council spokesman. "His reaction says a lot about who Pompeo is and, more importantly, how he represents America and our values around the world." Peter Weber

Dr. David Fajgenbaum couldn't wait for someone else to come up with a treatment for Castleman disease, the rare autoimmune disorder he was diagnosed with during his third year in medical school.

Fajgenbaum, 34, was hospitalized four times due to the disease, which caused his immune system to attack his organs. He had to go through chemotherapy in order to survive, and he came so close to death that a doctor once told him to write down his living will. "You learn a lot by almost dying," he told CNN.

Fajgenbaum's mother died of cancer while he was in college, and wanting to find a treatment in her honor, he studied at Oxford so he could learn how to conduct scientific research. Upon enrolling in medical school at the University of Pennsylvania, he decided he would become an oncologist. That changed after Fajgenbaum's diagnosis and his most harrowing hospitalization, six years ago. At the time, he noticed there were red spots on his skin, and when he questioned his doctors, they said they were nothing.

Once he recovered and graduated from med school, he formed the Castleman Disease Collaborative Network, inviting the best doctors and researchers to work with him. They needed to come up with some sort of a treatment, he decided, and fast. While looking at his medical charts, Fajgenbaum saw that a protein known as VEGF spiked every time he had a flareup of his disease. This protein controls the growth of blood vessels and gets the immune system going, and he wondered if this was linked to the red spots once on his skin. He asked his doctor to prescribe an immunosuppressant, and that did the trick — he's been in remission for five years. Now married, a new father, and a medical professor at the University of Pennsylvania, Fajgenbaum is thrilled to see the treatment working on other patients. Catherine Garcia

"The Fake News is saying that I am willing to meet with Iran, 'No Conditions,'" President Trump tweeted Sunday night. "That is an incorrect statement (as usual!)." Where would the news media get such an idea?

Here, for example, are Secretary of State Mike Pompeo and Treasury Secretary Steven Mnuchin saying Trump is willing to meet with Iran with no preconditions just last week.

Well, maybe Pompeo and Mnuchin just misunderstood Trump? Here's Trump in June.

And last year:

Assuming there isn't some esoteric difference between "no conditions" and "no preconditions," it appears that the "incorrect statement" came from the president himself. Add any parenthetical accentuation you see fit. Peter Weber

Talks between Venezuelan President Nicolás Maduro's government and the country's opposition party are officially done, six weeks after Maduro's representatives stopped attending the discussions.

Opposition leader Juan Guaidó made the announcement on Sunday. The talks, mediated by Norway and held in Barbados, were called as a way to try to end the escalating political crisis engulfing Venezuela. Millions of people have left the country, due to poverty, inflation, and food and medicine shortages. Guaidó, the leader of Venezuela's National Assembly, said Maduro was not fairly elected in 2018, and he is the legitimate president, an assertion backed by the United States and dozens of other countries.

The opposition tried to launch a military uprising in the spring, but it failed, and Maduro has retained power, refusing to step down. In August, his representatives left the talks, citing President Trump's new sanctions against the country. When talks were still taking place, the opposition called for a new, free election, but Maduro's representatives would not even broach the subject, Reuters reports. Catherine Garcia

Purdue Pharma, the drugmaker accused of playing a major role in the opioid epidemic, filed for Chapter 11 bankruptcy protection in New York on Sunday. The move was expected after the company and its owners, the Sackler family, reached a tentative settlement with 24 states and thousands of local governments last week. Under the settlement, the Sacklers would wash their hands of Purdue, putting up $3 billion of the family's estimated $13 billion fortune and turning Purdue into a trust, with profits from OxyContin and other drugs going to the plaintiffs.

This isn't the end of the road for Purdue yet, though, as The Associated Press explains.

The thousands of plaintiffs who have not yet signed on to the settlement, including about half of U.S. states, will likely object to the settlement in bankruptcy court, and there are open questions about whether the proposed settlement is really worth $12 billion and how the money would be distributed. Purdue and the lawyers representing the parties that agreed to the settlement argue that nobody is served by long, costly litigation.

Recent court filings suggest much of the Sackler wealth has been stashed offshore since 2008, making it likely out of reach of U.S. plaintiffs, especially if the company dissolves without admitting wrongdoing or being found guilty in court. "The Sacklers are going to be left with plenty of money after this,'' Adam J. Levitin, a bankruptcy expert at Georgetown Law, tells The Washington Post. "There is a desire that the Sacklers pay some blood money, but it's never going to be enough to make everyone happy.''

OxyContin accounts for only a slice of the opioid drugs sold in the U.S., but Purdue's aggressive and misleading marketing is blamed for helping spark the opioid addiction crisis. Since 1999, more than 200,000 people have died from overdoses of prescription opioids. Peter Weber

No deal was reached on Sunday between the United Auto Workers and General Motors, resulting in about 49,000 union members going on strike at midnight Monday.

This is the first national UAW strike since 2007, and was authorized Sunday morning in Detroit during a UAW meeting of regional leaders. The UAW said it is asking for more affordable health care, fair wages, and profit sharing, and could not reach an agreement with GM. "We stood up for General Motors when they needed us most," UAW Vice President Terry Dittes said in a statement. "Now we are standing together in unity and solidarity for our members, their families, and the communities where we work and live."

GM said it offered better health benefits and to create more than 5,400 new jobs, adding, "We have negotiated in good faith and with a sense of urgency. Our goal remains to build a strong future for our employees and our business." Contract talks will start back up again Monday morning, UAW spokesman Brian Rothenberg said. Catherine Garcia

In his new memoir, former British Prime Minister David Cameron says he believes current Prime Minister Boris Johnson only backed Brexit because "it would help his political career."

Cameron is candid when it comes to sharing his feelings about Johnson and Michael Gove, a fellow Conservative Party member who served in Cameron's cabinet and is now chancellor to the Duchy of Lancaster. U.K.'s Sunday Times published an excerpt of the memoir, in which Cameron calls the men "ambassadors for the expert-trashing, truth-twisting age of populism" and accuses Gove of being disloyal to both him and Johnson.

Because the Conservative Party's manifesto committed to holding a referendum on the U.K.'s membership in the European Union, Cameron called for a vote in 2016. The Leave campaign won, with 52 percent of the vote compared to Remain's 48 percent. Cameron was in favor of remaining, and he says Johnson merely took the "lead on the Brexit side — so loaded with images of patriotism, independence, and romance — [so he] would become the darling of the party." Johnson, he continued, "risked an outcome he didn't believe in because it would help his political career."

Cameron, who resigned as prime minister shortly after the vote, told the Times on Saturday that he understands "some people will never forgive me" for calling the referendum. Liberal Democrat leader Jo Swinson is one of those people, saying Cameron "put the interests of the Conservative Party ahead of the national interest." Catherine Garcia