WATERTOWN, Mass. —
"He is such an intelligent boy," the father said. "We expected him to come on holidays here."
According to the FBI, Dzhokhar Tsarnaev was seen setting down a bag at the site of the second of two explosions at the marathon finish line.
Insurgents from Chechnya and neighboring restive provinces in the Caucasus have long been involved in terrorist attacks in Moscow and other places in Russia.
In 2002, Chechen militants took 800 people hostage in Moscow and held them for two days before special forces stormed the building, killing all 41 captors. Also killed were 129 hostages, mostly from the effects of the gas Russian forces used to subdue the attackers.
Chechen insurgents also launched a 2004 raid in the southern Russian town of Beslan and took hundreds of hostages. The siege ended in a bloodbath two days later, with more than 330 people, about half of them children, killed.