Video: 'RAW: Watch Boston Marathon explosions'

(Sunday, April 15, 2013, 2:49:43 p.m. EST; during the Boston Marathon bombing) — Two bombs made from pressure cookers exploded today at the Boston Marathon finish line, killing two women and an 8-year-old boy and injuring more than 260, as one of this city’s most cherished rites of spring was transformed from a scene of cheers and sweaty triumph to one of screams and carnage.

Video: 'Boston Marathon Explosions: Terror at the Finish Line'

Almost three-quarters of the 23,000 runners who participated in the race had already crossed the finish line when a bomb that had apparently been placed in a garbage can exploded in a haze of smoke amid a crowd of spectators on Boylston Street, just off Copley Square in the heart of the city.

Thirteen seconds later, another bomb exploded several hundred feet away.

Pandemonium erupted as panicked runners and spectators scattered, and rescue workers rushed in to care for the dozens of maimed and injured, some of whom lost legs in the blast, witnesses said.

Video: ''5 Days': The Hunt for the Boston Marathon Bombers'

Suspected bomber Tamerlan Tsarnaev died in a shootout with police on Apr. 19, 2013; his brother, Dzhokhar Tsarnaev, was tried, convicted, and sentenced to death.

A federal appeals court threw out the death sentence, but the Supreme Court reinstated it in March 2022.

During questioning, Dzhokhar said that he and his brother were motivated by the wars in Iraq and Afghanistan, that they were self-radicalized and unconnected to any outside terrorist groups, and that he was following his brother’s lead.

He said they learned to build explosive devices from the online magazine of Al-Qaeda in the Arabian Peninsula.

He also said they had intended to travel to New York City to bomb Times Square.