7 things to know now: Sally Yates testifies; frat members arrested; new Oreo flavor

Here's a roundup of news trending across the nation and world today.

What to know now:

1. Suspected serial killer arrested: A former city bus driver has been arrested in the deaths of nine people in the Phoenix, Arizona area, Phoenix police said Monday. Aaron Saucedo, dubbed the Serial Street Shooter, is alleged to have stalked victims after dark then gunned them down as they stood outside their homes or sat in cars. Police have not said what motivated Saucedo to kill his victims.

2. Yates testifies: Sally Yates, the former acting U.S. attorney general, told a Senate subcommittee Monday that she warned the White House that national security adviser Michael Flynn had been "compromised" with the Russians, leaving him open to blackmail. In a three-hour hearing, Yates told senators she met with the White House counsel and told him that the story Vice President Mike Pence was telling the public about Flynn's dealings with the Russian ambassador to the United States was not true. Yates said she wanted to let officials know that Flynn had misled Pence.

3. Fraternity members charged: Eighteen members of a Penn State University fraternity are facing charges in the death of Timothy Piazza, an 18-year-old freshman who died as a result of a fall down stairs during a hazing ritual. The members of Beta Theta Pi will face charges after they failed to call for help until nearly 12 hours after Piazza was injured.

4. Man arrested after punch: A man who killed a California father of five outside of a Las Vegas lounge had served time in jail on attempted murder charges. James Michael Beach, 27, was arrested Sunday in the death of Luis Campos, 45. Beach allegedly punched Campos in the face as he stood outside of the Vanguard Lounge. Witnesses say Beach was walking past the lounge, asked what Campos was looking at, and punched him. Campos never regained consciousness. Beach's attorney said Beach didn't mean to kill Campos, and will plead not guilty to the murder charge.

5. A longer life: A study released Monday shows that where you live in the United States can have a significant effect on how long you live. People in Colorado can live as much as 20 years longer than those who live in the Dakotas and the Mississippi River basin, researchers say. A combination of poor diet, lack of exercise, economic status and ethnicity were reasons researchers gave for the different life expectancies.

And one more

As if it weren't enough that the new Oreo flavor showed up in stores on Monday, now Nabisco, the company that makes cookies, has announced they will let consumers have a hand in creating the next flavor. Nabisco is asking devotees of the sandwich cookie to submit their ideas for the next Oreo flavor via the Twitter hashtag #MyOreoCreation for the chance to win $500,000.

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