IE 11 is not supported. For an optimal experience visit our site on another browser.

KNOW IT ALL: Wednesday's Top Stories at NBC News

Here's a look at today's key headlines.

Good morning. Here are some of the stories we're following today:

1. Brussels Suicide Bombers Were Brothers: Sources

Two brothers were identified by police sources early Wednesday as the suicide bombers behind the Brussels terror attacks as the search for an on-the-run suspect intensified. Khalid El Bakraoui, 27, and 30-year-old sibling Ibrahim blew themselves up on Tuesday morning. Both had been convicted of violent crimes in the past and had links to one of the Paris attackers. Read more in NEWS.

2. American Couple Missing After Deadly Brussels Blasts

An American husband and wife remained missing more than 24 hours after deadly blasts rocked Brussels, family members told NBC News. Justin and Stephanie Shults had just dropped off her mother at the Belgian capital's airport when two blasts killed at least 11 people in the check-in lounge. Read more in NEWS.

3. Sanders Wins Idaho and Utah, Clinton and Trump Take Arizona

Tuesday's primaries and caucuses were a mixed bag as Sen. Bernie Sanders took two states — Idaho and Utah — to Hillary Clinton's lone win in Arizona, and Donald Trump and Sen. Ted Cruz split the Republican races in Arizona and Utah respectively, NBC News projects. Read more in POLITICS.

4. Jeb Bush Endorses Ted Cruz, Urges GOP to Reject Trump

Jeb Bush endorsed Republican presidential candidate Ted Cruz on Wednesday in a rebuke to what the former Florida governor called the "divisiveness and vulgarity" of Donald Trump. Read more in POLITICS.

5. Supreme Court Vacancy Complicates Birth Control Fight

The effect that conservative Justice Antonin Scalia's death is having on the Supreme Court's most divisive issues will get another big test when the court convenes Wednesday in the battle pitting religious freedom and birth control. Read more in POLITICS.

6. Family Appeals to Keep Girl Removed Over Native Ancestry

The longtime foster family of a 6-year-old part-Native American girl who was taken from their home because of her heritage filed an appeal Tuesday with the California court in an effort to get her back. Read more in NEWS.

7. Ex-State Dept. Worker Sentenced For 'Sextortion'

An ex-State Department worker was sentenced to nearly five years in prison Tuesday for operating a massive hacking and “sextortion” scheme out of the U.S. Embassy in London, federal prosecutors said. Read more in NEWS.

8. Sarah Palin to Embark on New Gig: TV Judge

Former Alaska Governor and one-time GOP vice presidential candidate Sarah Palin is embarking on a new gig: daytime TV judge. The program is still unnamed, said publicist Howard Bragman, who is working with Palin on the project. But he told NBC News that Republican star — who recently endorsed presidential contender Donald Trump — that Palin will do her best "Judge Judy,” mediating and deciding cases brought before her fictional court. Read more in POLITICS.