Boston bombing suspect Dzhokhar Tsarnaev reportedly told investigators that he and his deceased brother were motivated by religious fervor but acted alone when they attacked the Boston Marathon on April 15, according to multiple outlets.

A senior government official told NBC that Dzhokhar, who is in serious condition after suffering gunshot wounds to his throat and tongue in addition to his leg and hand, was cooperative as he gave written responses or answered questions by nodding yes or shaking his head no.

Earlier Monday U.S. officials charged the 19-year-old, a naturalized U.S. citizen of Chechen origin, with one count of using and conspiring to use a weapon of mass destruction and one count of malicious destruction of property with an explosive device.

CNN reports Dzhokhar said his older brother, Tamerlan, planned the Boston Marathon bombing — which killed three and wounded more than 180 — and Newsday reports that Dzhokhar said they learned how to make pressure cooker bombs on the Internet.

Tamerlan, 26, died during a gunfight with police in Watertown, Mass. late Thursday night. Earlier we reported how the former amateur boxer became increasingly devout and confrontational about his Islamic beliefs in the past couple of years.

In November and January Tamerlan interrupted speakers at the Islamic Society of Boston mosque in Cambridge, Mass. — one for comparing the Prophet Mohammed to Martin Luther King, Jr. and the other saying it's OK to celebrate American holidays.

A Wall Street Journal report notes that Tamerlan seemed to have a "domineering effect" on Dzhokhar:

Gilberto Junior, owner of Junior Auto Body in Somerville, Mass., who regularly worked on the brothers' cars, said Dzhokhar was sociable when he came in by himself but silent with his brother.

Dzhokhar agreed to "voluntary detention," and a probable cause hearing was set for May 30. He is likely to face state charges in the shooting death of MIT police officer Sean Collier.

