5 Things to Know This Morning

May 21, 2013— -- Your look at the five biggest and most buzz-worthy stories of the morning.

1. At Least 20 Kids Among the Dead in Okla. Twister
At least 20 of the 51 people killed by a devastating monster tornado that ripped through Moore, Okla., were children, the Oklahoma Chief Medical Examiner said overnight, as searchers picked through the rubble of schools, homes and businesses leveled by the storm.

2. Oklahoma Tornado Hit Wind Speeds of 200 MPH
The National Weather Service said the preliminary rating of the Newcastle-Moore tornado was at least EF-4, meaning wind speeds of up to 200 mph, and traveled a distance of 12 miles.

3. White House Chief of Staff Knew About IRS Investigation Last Month
White House Press Secretary Jay Carney told reporters yesterday that Chief of Staff Denis McDonough and "other members of the senior staff" knew about the investigation into the IRS targeting conservative groups last month. President Obama has said he learned about the scandal weeks later by watching the news.

4. Apple CEO to Testify on Capitol Hill
Apple CEO Tim Cook will take the stand at a congressional public hearing today, a day after investigators say the company avoided billions of dollars in taxes by using a complex, global web of subsidiaries.

5. Arias Jury to Decide Life or Death
Both sides are expected to rest their case today in the death penalty phase of Jodi Arias' trial. The jury will go into deliberations to decide whether to sentence Arias to death or life in prison.