Howard Berkes

Updated at 4:50 p.m. ET

Investigators in Las Vegas are sifting through evidence they've gathered from the homes of the man who sprayed a concert crowd with gunfire. They've begun to interview his girlfriend. They've learned quite a bit about Stephen Paddock's past and preparation, but there is still no explanation for why he damaged and destroyed so many lives.

The second-highest ranking member of the Florida Senate pledged a legislative review of a state law that has allowed injured undocumented workers to be arrested and potentially deported rather than paid workers' compensation benefits.

"Legitimate injuries shouldn't be denied just because the person was an undocumented immigrant," said Republican Sen. Anitere Flores, the president pro tempore of the state Senate and chairwoman of the Banking and Insurance Committee.

NPR's ongoing investigation of the advanced stage of the fatal lung disease that afflicts coal miners has identified an additional 1,000 cases in Appalachia.

That brings the NPR count of progressive massive fibrosis, the most serious stage of the disease known as black lung, to nearly 2,000 cases in the region, all of which were diagnosed since 2010.

Former Massey Energy CEO Don Blankenship is marking his release from federal custody with an appeal for vindication by the U.S. Supreme Court.

Blankenship served a one-year federal prison sentence after being convicted of conspiracy to violate federal mine safety laws. The charges stemmed from the disaster at a Massey Energy mine in West Virginia in 2010 that left 29 coal miners dead.

West Virginia's Democratic candidate for governor is a billionaire, a philanthropist and a resort and coal mine owner who cites his business and mining experience as major attributes as he seeks to lead his home state out of a severe budget and economic crisis.

"I am not a career politician; I am a career businessman," wrote Jim Justice in an April 5 op-ed that appeared in the Charleston Gazette-Mail.

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