HispanicBusiness

April 16--IT WAS 4 hours, 9 minutes and 43 seconds into Monday's Boston Marathon and Randy Clever -- a 63-year-old retired city worker from Germantown -- was just a few weary steps from the finish line and beginning to raise his hands in triumph when he heard a loud boom.

In his red singlet and blue hat, Clever looked over his shoulder and raised his hands even higher, this time in fear.

"I thought it was some kind of explosion," he said. "But I didn't think it was a bomb. . . . When the second explosion happened, I knew it was a bomb."

The Philadelphia man was at ground zero for a new American tragedy, a brazen assault on one of the nation's best-known marathons that left at least three people dead, including an 8-year-old boy, and injured more than 140 others in the worst bombing on American soil since the 9/11 attacks .

The two explosive devices went off at 2:50 p.m. on a cool and partly sunny day in Boston. The bombs detonated after most of the 23,000 runners had already crossed the finish line in Copley Square, cheered on by a large throng of spectators enjoying Massachusetts' Patriots' Day holiday and packing the city's narrow streets.

The blasts, just about 12 seconds apart, were captured by several news and video cameras poised near the finish line that showed a bright orange flash on the sidewalk followed by a plume of dense smoke. The force of the explosion appeared to blow back several runners -- including a 78-year-old man from Washington state who crumpled to the pavement -- before first responders raced to sidewalks stained in deep-red blood to tend to the injured.

The latest reports Monday night said in addition to the three known fatalities, at least 144 others were treated for injuries -- about 15 of them critical -- at Boston-area hospitals. CNN reported there had been 10 amputations.

As many as a dozen of the injured were reportedly children. Ironically, marathon officials had dedicated the last mile of the course where the explosions took place to the 20 first-graders who were killed in December in the Newtown, Conn., school massacre. And authorities Monday night were still testing other suspicious devices that had been found on or near the marathon route.

The midafternoon mayhem came as something of a shock to the American psyche. Politicians, pundits and the public had been debating domestic gun violence while more overt acts of terrorism, and the fears that such acts inspire, were seemingly starting to fade into a past era, a time that many had hoped ended with the killing of 9/11 mastermind Osama bin Laden in 2011.

Early in the evening, President Obama seemed to echo the grim cadences of that time when he appeared in the White House press-briefing room to declare: "We will find out who did this; we'll find out why they did this. Any responsible individuals, any responsible groups will feel the full weight of justice."

Just like after 9/11, there were numerous reports of "secondary devices" in Boston hotels or elsewhere in the New England city -- although most of those reports, such as a suspicious fire or blast at the John F. Kennedy Library on the outskirts of the city, proved ultimately to be unfounded or unrelated.

Mayors and police commissioners in major U.S. cities announced stepped-up security while boosting police presence in train stations and other public