Overview: 2013/04/18 Headlines: Massive Blast Causes Casualties at Texas Fertilizer Plant; Authorities Spot At Least 1 Suspect in Boston Marathon Videos; Senate Kills Gun Reform with Defeat of Every Key Measure; Obama Decries "Shameful Day" After Senate Defeat of Gun Control; 4 Dems Join Republicans to Defeat Gun Reforms; GOP Bid to Override Concealed Carry Laws Fails; Gun Violence Survivor Removed from Senate Gallery After Yelling "Shame on You"; Giffords Denounces Senate for Blocking Gun Control; Mississippi Resident Detained for Ricin Letters; Supreme Court Rejects Human Rights Cases Against Foreign Corporations; Wife of Jailed Texas Official Says Husband Killed Prosecutors; Maduro Blasts Kerry for Rejecting Venezuelan Election Win; Palestinians Stage Prisoners Day Rallies; Israeli Military Court Jails Palestinian-American Teen for Throwing Rocks; Military Appeals Court Rejects Secrecy Challenge in Manning Trial