Merrit Kennedy

Dylann Roof, who gunned down nine people in the basement of a historically black church in Charleston in 2015, pleaded guilty to murder charges at a South Carolina state court.

In exchange, a circuit judge is expected to hand down a life sentence Monday afternoon, as The Post and Courier reported.

For the second consecutive year, aerial surveys show severe coral bleaching in the Great Barrier Reef off the coast of Australia.

While severe bleaching events have occurred three other times in the past 20 years — in 1998, 2002 and 2016 — this year marks the first time it's known to have happened two years in a row. Scientists say the damage is caused by higher water temperatures due to global warming.

In an elaborate ceremony, Thailand's king has signed the country's military-backed constitution. The document paves the way for Thailand to hold elections in the coming months, but critics say it only solidifies the power of the military.

Updated at 12:18 p.m. ET

House Intelligence Chairman Devin Nunes says he is temporarily stepping aside from the committee's probe into Russian meddling in the 2016 election, as the House Ethics Committee opens an inquiry into whether he improperly disclosed classified information.

Nunes will continue to serve as the committee's chairman and remain involved in other matters before the panel. Rep. Mike Conaway, R-Texas, will take the lead on the Russia investigation.

A dog is being credited with saving lives by intervening to stop a suicide bomber who was attempted to enter a wedding party near Maiduguri, Nigeria.

Army radio says that the dog grappled with the teen girl bomber until the explosives went off, killing them both, as NPR's Ofeibea Quist-Arcton reports.

"Most Belbelo villagers were reportedly at the wedding when the dog pounced on the would-be suicide bomber, who was reportedly hovering on the outskirts of the ceremony on Sunday morning," Ofeibea adds.

A huge, internally flawless, 59.60-carat diamond called the "Pink Star" went for a whopping $71.2 million at auction in Hong Kong — the highest price ever for a jewel.

The oval gem was purchased at Sotheby's by Hong Kong-based jewelry company Chow Tai Fook in a bid placed over the phone by the chairman, who renamed the jewel "CTF PINK STAR" in honor of his late father.

Former Maricopa County Sheriff Joe Arpaio routinely pointed to the notorious, outdoor Tent City Jail he opened in the 1990s as a symbol of his "tough on crime" stance. Inmates live in tents through the sweltering Arizona summer heat and are issued old-fashioned striped prison jumpsuits and pink underwear.

Now, it's shutting down.

This story starts with the mystery of a missing cow.

University of Utah researchers placed seven cow carcasses in Utah's Great Basin Desert, and set up cameras to learn about the behavior patterns of local scavengers.

But a week later, researcher Evan Buechley returned to one of the sites and found no sign of the cow.

A powerful South African union federation that had been a key ally of President Jacob Zuma has become the latest group to join the rising calls for him to resign.

"There has never been so much pressure on him to go, from allies and opponents," NPR's Ofeibea Quist-Arcton reports, adding that Zuma's problems began with the widespread perception that he was mired in corruption scandals.

Updated at 3:50 p.m. ET

Russian investigators say an "explosive device" ignited and ripped through a train car as it was traveling in between metro stations in St. Petersburg, Russia, on Monday afternoon. A second, unexploded device was found at a different metro stop.

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