Dick Trickle, a "short-track hero" in the '70s and '80s who moved to the NASCAR circuit later in his career, died Thursday.

According to The Charlotte Observer, the 71-year-old was killed by "an apparent self-inflicted gunshot wound, Lincoln County [N.C.] deputies said."

In a message written on a wall of the boat where he was found hiding, Boston bombings suspect Dzhokhar Tsarnaev claimed responsibility for the attack and said it was motivated by anger over the Afghan and Iraq wars, sources familiar with what was found have told CBS News correspondent John Miller.

"A massive emergency response" is underway in North Texas, where tornadoes blew through Wednesday night, The Dallas Morning News says. A twister that hit Granbury, about 35 miles southwest of Fort Worth, left at least six people dead, more than 100 injured and even more homeless, The Associated Press adds.

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The news that U.S. scientists have successfully cloned a human embryo seems almost certain to rekindle a political fight that has raged, on and off, since the announcement of the creation of Dolly the sheep in 1997.

"The issue of legislation on human cloning is about to get hot again," says Hank Greely, director of the Center for Law and the Biosciences at Stanford Law School.