ROUGH CUT - NO REPORTER NARRATION<br/> <br />Amateur video filmed by Boston Marathon runner Jennifer Treacy on Monday (April 15) showed one of two explosions that went off near the the finish line.<br/> <br />Treacy, who had been documenting various parts of her run to show her family, captured the explosion which can be seen from her left as she neared the end when a bombing attack killed three people and wounded more than 100 others.<br/> <br />It was the worst bombing on U.S. soil since security was tightened after the attacks of Sept. 11, 2001.
