Timeline: Boston Marathon bombings

Published On: Apr 16 2013 11:30:08 AM CDT   Updated On: Jul 10 2013 03:08:11 PM CDT

With Boston Marathon bombing suspect Dzhokhar Tsarnaev pleading not guilty Wednesday in his first court appearance since being arrested, revisit a timeline of the events in the case so far.

Marathon explosion White House
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4 p.m. -- U.S. Secret Service agents expand the security perimeter around the White House complex in Washington, D.C., and shut down parts of Pennsylvania Avenue.

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