Boston Marathon bombing suspect Dzhokhar Tsarnaev downloaded bomb-making instructions from an al Qaeda magazine, gathered online material on Islamic jihad and martyrdom, and later scribbled anti-American messages inside the boat where he lay wounded, a US federal indictment has charged.
The 30-count indictment includes the bombing charges, punishable by the death penalty, that were brought against the 19-year-old Tsarnaev in April. But prosecutors added charges covering the slaying of an MIT police officer and the carjacking of a motorist during the getaway attempt that left Tsarnaev's older brother, Tamerlan, dead.
Three people were killed and more than 260 wounded by the two pressure-cooker bombs that went off near the finish line of the marathon on April 15.
Dzhokhar Tsarnaev was captured four days later, hiding in a boat parked in a backyard in Watertown, Massachusetts.
According to the indictment, he scrawled messages on the inside of the vessel that said, among other things, "The US Government is killing our innocent civilians," ''I can't stand to see such evil go unpunished," and "We Muslims are one body you hurt one you hurt us all."
The Tsarnaev brothers had roots in the turbulent Russian regions of Dagestan and Chechnya, which have become recruiting grounds for Islamic extremists. They had been living in the US about a decade.
But the indictment made no mention of any larger conspiracy beyond the brothers, and no reference to any direct overseas contacts with extremists. Instead, the indictment suggests the Internet played a central role in the suspects' radicalization.
Sometime before the attack, Dzhokhar Tsarnaev downloaded onto his computer the summer 2010 issue of Inspire, an online English-language magazine published by al Qaeda, according to the indictment. The issue detailed how to make bombs from pressure cookers, explosive powder extracted from fireworks, and lethal shrapnel.
He also downloaded various pieces of extremist Muslim literature, including "Defence of the Muslim Lands, the First Obligation after Imam," which advocates "violence designed to terrorise the perceived enemies of Islam, among other things," the indictment said.
One tract downloaded included a foreword by Anwar al-Awlaki, an American propagandist for al Qaeda who was killed in a US drone strike, federal prosecutors said.
The indictment assembled and confirmed details of the case that have been widely reported over the past two months, and added new pieces of information.
For example, it confirmed that Tamerlan Tsarnaev bought 48 fireworks mortar shells containing about eight pounds of explosive powder from a Seabrook, New Hampshire, fireworks store. It also disclosed that he used the Internet to order electronic components that could be used in making bombs.
The papers detail how, after using the Internet to study jihad propaganda and bomb-making instructions, the brothers placed knapsacks containing shrapnel-packed bombs near the finish line of the 26.2-mile race.
The court papers also confirm that Dzhokhar Tsarnaev inadvertently contributed to his brother's death by running him over during a shootout with police.
The charges also cover the slaying of Massachusetts Institute of Technology police officer Sean Collier, who authorities say was shot in his cruiser by the Tsarnaevs during their getaway attempt. The brothers tried to take his gun, prosecutors said.
At the same time the federal indictment was announced, Massachusetts authorities brought a 15-count state indictment against Dzhokhar Tsarnaev over the MIT officer's slaying and the police shootout.