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

KNOW IT ALL: Thursday's Top 7 Stories at NBC News

A look at the key headlines.

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

1. Trump Warns of Riots if He Doesn’t Get GOP Nod

Donald Trump is warning that his supporters would respond with "riots" if he fails to secure the nomination at July's convention in Cleveland. Far from idle chatter, Trump's words come as escalating protests from left-wing activists, heated responses from his supporters and increasing tensions within the GOP over his candidacy are raising fears that the Republican convention could devolve into chaos. Read more in POLITICS.

2. GOP Leaders Double Down to Block SCOTUS Pick

Congressional Republicans reiterated on Wednesday that they have no intention of taking any action on President Barack Obama's Supreme Court pick, Merrick Garland — a defiant position that foreshadows a tense confirmation fight. Read more in POLITICS.

3. American ISIS Fighter an Intelligence ‘Gold Mine’

U.S. officials are eager to question an alleged American ISIS fighter captured in Iraq on Monday because he could be a treasure trove of intelligence about how ISIS really works. Read more in INVESTIGATIONS.

4. Suit Claims Chief Federal Judge Raped Teen

Richard W. Roberts, the chief U.S. district judge for Washington, D.C., could face a congressional investigation in connection with a sexual abuse lawsuit filed Wednesday by a Utah woman. Read more in NEWS.

5. SeaWorld to End Breeding Program for Orcas

The entertainment park announced Thursday it will end its orca whale breeding programs and take what it called a "new direction" amid changing social attitudes. Read more in NEWS.

6. Frank Sinatra Jr., Son of Singer, Dies at Age 72

The younger Sinatra died unexpectedly of cardiac arrest while on tour in Florida, the Sinatra family said. Sinatra Jr. was the son of Sinatra's first wife, Nancy Barbato Sinatra, and the younger brother of Nancy Sinatra, who had a successful musical career of her own. Read more in POP CULTURE.

7. Meet the Transgender Model Making History

Benjamin Melzer, 29, is appearing on the limited edition collector's cover of Men's Health magazine in Germany after entering a competition that included votes from readers and social media users. Read more in NEWS.

Nightly Spotlight

It's the end of the road for Los Angeles' famous Sixth Street Bridge after cementing its place in history.

We apologize, this video has expired.