Need to Know News: Feds probe Florida teen death; Dozens killed in widespread attacks on Iraq invasion anniversary

Each day, we here at "Piers Morgan Tonight" put together the news you need to know – from what happened last night to what will happen today.

For March 20, 2012 – Feds probe Florida teen death, Dozens killed in widespread attacks on Iraq invasion anniversary and Peyton Manning picks the Broncos...

• Feds probe Florida teen death: "Federal prosecutors and the FBI have opened an investigation into the killing of an unarmed teen by a neighborhood watch volunteer in Florida. The death drew protesters Monday to the courthouse in Seminole County, north of Orlando, to demand justice for Trayvon Martin, the 17-year-old who was shot and killed last month while walking back to his father's fiancee's house in Sanford."

• Dozens killed in widespread attacks on Iraq invasion anniversary: "A spate of car bombings rocked Iraq on Tuesday, the ninth anniversary of the U.S. invasion and days before the nation hosts a meeting of Arab leaders. The violence left at least 41 people dead and 190 wounded, officials said."

• Video of toddler's screening at airport fuels criticism: "A 2010 video of an airport screener patting down a 3-year-old boy in a wheelchair has become the latest Rorschach test of the public's attitude towards the TSA, pitting agency defenders against those who say the video shows the child being treated like a terrorist."

• Google nabs Digg founder to boost Google+: "One of Silicon Valley's iconic entrepreneurs is going corporate. Google has scooped up Digg founder Kevin Rose and a number of his employees at Milk, the venture he created last year as a lab for experimenting with mobile app ideas."

• Peyton Manning picks the Broncos: "Despite not being a favorite at the opening of the Peyton Manning free-agency proceedings, Denver swooped in and stole the future Hall of Famer, as news came Monday that Manning had decided to play for the Broncos and instructed his agent to begin negotations with the team. That news left the Titans, 49ers and others as disappointed bystanders."

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