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

Image: U.S. Republican presidential candidate Ted Cruz speaks with supporters of fellow candidate Donald Trump at a campaign event outside The Mill in Marion, Indiana
U.S. Republican presidential candidate Ted Cruz (R-TX) speaks with supporters of fellow candidate Donald Trump at a campaign event outside The Mill in Marion, Indiana, U.S., May 2, 2016.AARON P. BERNSTEIN / Reuters

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

1. Cruz Fights for Indiana Lifeline as Trump Moves In for the Kill

It's been a long, strange trip — but the Republican primary may finally be coming to an end in Indiana on Tuesday. Cruz on Monday presented himself as the one reliable conservative in the race and warned in an NBC News interview that Trump was "a big-government New York liberal" in the mold of Hillary Clinton who would sell out the right on issues like guns and abortion. Read more in POLITICS.

2. Trump's Lead Continues to Grow Nationally: Poll

Following businessman Donald Trump's landslide primary victories last week, his support among Republican and Republican-leaning voters nationally is up 6 points. Trump has hit 56 percent support, his highest yet in the NBC News|SurveyMonkey Weekly Election Tracking Poll. Read more in POLITICS.

3. American Serviceman Dies in Iraq

An American serviceman has been killed in combat in Iraq, officials said Tuesday.The U.S.-led coalition issued a statement saying one of its service members died in northern Iraq on Tuesday as "a result of enemy fire." It did not specify the victim's nationality, but Defense Secretary Ash Carter confirmed that an American serviceman died near the Iraqi city of Irbil. Read more in NEWS.

4. Hillary Clinton Apologizes to Coal Country

Hillary Clinton, in a rare candid moment on the trail, apologized to a man who confronted her over comments made earlier this year about putting coal miners "out of business." Read more in POLITICS.

Hillary Clinton speaks to Bo Copley about a photograph of his children during a campaign event in Williamson, West Virginia on May 2.JIM YOUNG / Reuters

5. Image Released of Missing Florida Mom

The last known photo of an Air Force veteran who vanished in South Florida last week was released Monday and appeared to show Tricia Todd, 30, "in good spirits," Martin County Sheriff William Snyder said. During a news conference, authorities said the image was taken by a surveillance camera at a grocery store in Hobe Sound, Fla., on Tuesday night, just a few hours before she disappeared. Read more in NEWS.

6. Former 49ers Player Charged With Raping Disabled Woman

Former San Francisco 49er Dana Stubblefield was charged Monday with the rape of a disabled woman following an investigation that lasted over a year, according to the Santa Clara County District Attorney's Office. Stubblefield, 45, faces five felony counts related to the alleged assault, the DA’s office said. Read more at NBC BAY AREA.

7. Celebs Shock & Awe at Met Gala

Celebrities feted the annual Met Gala on with sparkly metallics and shiny, futuristic-looking fabrics Monday night during the annual fundraising bash in New York City. See more in PHOTOS.

Nightly Spotlight: Can't Sleep? New Study Says Try Therapy, Not Pills

People with insomnia should try counseling before they turn to pills, which often carry dangerous side-effects, a doctors' group advised Monday.