The surviving suspect in the Boston bombings has told investigators that he and his brother were inspired partly by watching online videos of a radical Muslim cleric who was killed by the U.S. in 2011, a U.S. official said, offering a new glimpse of the brothers' alleged radical turn that echoes earlier terrorism cases.

Anwar al-Awlaki, a U.S. citizen living in Yemen, was killed by a U.S. drone strike. He previously played a role in the radicalization of 'underwear bomber' Umar Farouk Abdulmutallab of Nigeria, who pleaded guilty to trying to blow up a U.S.-bound airliner on Christmas Day 2009.

Unlike Mr. Abdulmutallab, who traveled to Yemen for instruction from Mr. Awlaki, investigators haven't found evidence of direct contact between the Tsarnaevs and the radical cleric, the U.S. official familiar with the suspect's statements said.

The brothers -- Tamerlan Tsarnaev, 26, and Dzhokhar Tsarnaev, 19 -- are accused of setting off two bombs at the Boston Marathon on April 15, killing three people and injuring more than 200. Dzhokhar Tsarnaev was arrested on April 19, a Friday, and answered investigators' questions over the subsequentweekend from his hospital bed, where he was receiving treatment for injuries suffered in a firefight with police.

An earlier gunfight with police killed Tamerlan Tsarnaev, whose body was turned over to a funeral service retained by his family on Thursday afternoon, a Massachusetts state spokesman said.

Officials have said Dzhokhar Tsarnaev stopped speaking to interrogators after being informed of his right to remain silent by a magistrate judge on April 22.

Officials have said that during interrogations the younger brother described the attack as motivated by jihadist ideology and suggested he and his brother grew radicalized online.

Also, Mr. Tsarnaev told interrogators he and his brother had considered carrying out their attack on July 4, but settled on April 15, which was celebrated as Patriots' Day in Massachusetts, the U.S. official said. Officials said Mr. Tsarnaev said the brothers built their pressure-cooker bombs in the older brother's Cambridge, Mass., apartment.