Mark Memmott

Update at 8:44 p.m. ET. Authorities Make An Arrest:

Authorities have made an arrest in connection to the suspicious envelopes sent to a senator and President Obama.

The FBI identified the suspect as Paul Kevin Curtis.

The The Clarion Ledger reports:

"The wife of a former justice of the peace is being held on a capital murder charge in the killings of the Kaufman County District Attorney, his wife and a top prosecutor," The Dallas Morning News reports.

Pat Summerall was the "voice of football and always will be," longtime broadcasting partner John Madden said Tuesday.

Margaret Thatcher, the prime minister whose time leading Great Britain in the 1980s brought joy to conservatives and despair to liberals, was remembered Wednesday for "a life lived in the heat of political controversy."

With her death last week at the age of 87, "there is great calm" for the Iron Lady, added the bishop of London, the Right Reverend Richard Chartres, during a funeral service at London's St. Paul's Cathedral.

(Note at 7:50 a.m. ET, April 18: We've begun a new post to track Thursday's developments.)

Investigators made progress Wednesday, as they tried to determine who planted two bombs near the finish line of the Boston Marathon, leaving three people dead and injuring about 180.

There will be many heartbreaking stories in coming hours and days about the victims of Monday's bombings at the Boston Marathon.

Among the first such tragic tales is that of the Richard family from Dorchester, Mass.

As the local Dorchester Reporter writes:

There was a 7 percent surge in housing starts last month, the Census Bureau and Department of Housing and Urban Development report.

As The Associated Press notes, the pace of construction — 1.04 million starts, at an annual rate — is the fastest in nearly five years and is another sign that the housing sector continues to recover from its 2007-08 crash.

There's been a strong earthquake, with an estimated magnitude of 7.8, in southeastern Iran near the border with Pakistan, the U.S. Geological Survey reports.

The temblor was centered about 53 miles east southeast of the small city of Khash. According to USGS, it was about 9.4 miles deep.

The day after two bombs exploded near the finish line of the Boston Marathon, investigators began to unravel some of the details of what happened, and we began to learn about the lives of the three people who were killed.

FBI Special Agent in Charge Richard DesLauriers said that they believed the devices used in the attack may have been pressure-cooker bombs stuffed with BBs and nails. Investigators said the bombs may have been left inside nylon bags or backpacks.

The Two-Way, NPR.org and some of NPR's Twitter accounts were hacked late Monday by an organization that's said to support Syrian President Bashar Assad's regime, as this statement from NPR reports:

Smashing through walls and yelling "Oh, Yeah!" apparently aren't cool enough for Kool-Aid Man anymore.

Ethiopian runner Lelisa Desisa won the men's division at this year's Boston Marathon on Monday, finishing the 26.2 miles in 2 hours, 10 minutes and 22 seconds. It's the first win at Boston for the 23-year-old.

How wrong was Punxsutawney Phil when the groundhog said on Feb. 2 that we'd have an early spring?

Here's a fresh headline that may be welcome to those who oppose the bipartisan plan to extend background checks of gun purchasers to sales made at gun shows and over the Internet:

Since President George W. Bush left office in 2009, The Dallas Morning News writes, he has been "a punching bag for [President] Obama, Democrats and even some Republicans."

But while Bush told the Morning News during an interview for a long story posted over the weekend that "nobody likes to be criticized all the time," he also indicated that the criticism hasn't caused him to question his decisions:

"I'm comfortable with what I did," he said. "I'm comfortable with who I am."

Good morning.

Our early headlines:

-- Threats And Crises Are 'Just Normal North Korean Diplomacy'

-- Venezuela Says Recount Likely After Chavez Heir's Close Win

Jenna Bush Hager, daughter of former President George W. Bush and former first lady Laura Bush, gave birth over the weekend to a girl.

Margaret Laura "Mila" Hager is named for her grandmothers, the former president announced in a statement. According to The Associated Press, the little girl's nickname is pronounced MEE-luh.

Search the morning-after stories about Sunday's dramatic finish at golf's Masters Tournament and one thing becomes clear. Adam Scott, the 32-year-old Australian who won after a two-hole playoff with Argentina's Angel Cabrera, seems to be one heck of a guy:

Monday is "the day of the sun" in North Korea — a celebration of founder Kim Il Sung's birth in 1912.

A surprisingly small victory margin for Hugo Chavez's hand-picked successor in Sunday's special presidential election looks likely to be followed by a recount in Venezuela.

Chavez, Venezuela's fiery, controversial and charismatic leader, died on March 5.

Jonathan Winters, known to one generation for his 1960s comedy albums, frequent Tonight Show with Johnny Carson appearances and comic movie characters, and to another generation as Robin Williams' baby on Mork & Mindy, has died. The news is coming from The Associated Press, TMZ, the NPR Arts Desk and other news outlets.

Winters was 87. TMZ says he died Thursday night "of natural causes in Montecito, Calif. ... surrounded by friends and family.

Mattel says its "Dolls of the World" line of Barbies come with passports, stamps and, with many of the toys, an "animal friend."

Update at 11:50 a.m. ET. Radio 1 Will Play A Snippet:

There's word from NPR's Philip Reeves in London that BBC's Radio 1 now says its weekend Official Chart show will play "a clip in a journalistic environment" of "Ding Dong The Witch Is Dead," which critics of former Prime Minister Margaret Thatcher pushed up the British charts this week after the Iron Lady's death.

The BBC has more:

Authorities in Arizona say a package addressed to controversial Maricopa County Sheriff Joe Arpaio was safely destroyed Thursday after a test for explosive residue confirmed it "contained black powder," The Arizona Republic writes.

A steep drop in gasoline costs fueled a 0.6 percent decline in wholesale prices from February to March, the Bureau of Labor Statistics says.

Excluding the volatile food and energy sectors, the so-called core rate of inflation was also in check: those prices rose a modest 0.2 percent.

Talk about an expensive bust:

Walking a line meant to show both resolve and willingness to trust in diplomacy, Secretary of State John Kerry warned North Korea on Friday not to engage in more warmongering — but also said the U.S. is willing to talk with that communist state if it's serious about discussing denuclearization.

"No one is going to talk for the sake of talking," Kerry said, but the U.S. does want to see a peaceful resolution of the latest crisis on the Korean peninsula.

"Sandy has been retired from the official list of Atlantic Basin tropical cyclone names by the World Meteorological Organization's hurricane committee because of the extreme impacts it caused from Jamaica and Cuba to the Mid-Atlantic United States in October 2012," the National Oceanic and Atmospheric Administration writes.

The storm names are administered by the World Meteorological Organization.

Play has begun at the 77th Masters in Augusta, Ga., and again this year the big question is whether Tiger Woods is really "back" and will win his first major championship since 2008.

The first national gun control legislation since the Dec. 14 school shooting in Newtown, Conn., is going to be debated on the floor of the Senate and appears headed for a vote sometime next week.

Supporters in the Senate on Thursday morning rounded up more than the 60 votes necessary to clear a procedural hurdle that could have held up consideration of the Democratic-crafted package. The vote was 68-31 in favor of blocking a bid by some Republicans to filibuster the legislation.