The Los Angeles Times reported that the Vatican tweeted the big news within minutes of Francis’ balcony appearance.

Read a New York Times story on the two brothers and what may have led them to abandon fairly normal lives for acts of terrorism.

Read an April 19, 2013 article in the New Republic about the influences on the Boston Marathon bombers.

Read an April 22 interview in The New Republic with terrorism expert Olivier Roy, who argues that the Boston suspects are more like the Columbine or Sandy Hook shooters. Roy says they have minimal connections to Islam as a religion but “are self-radicalizing in a Western environment.”

In a Religion Dispatches column, Mark Juergensmeyer argues that religious motivations are not central to “lone wolf” attacks like the bombings in Boston.

Read an April 22, 2013 essay at Wired.com that examines extremism under the lens of psychology.

Andrew Brown of The Guardian has an April 25 column exploring why some violent organizations feed off religion and others are atheistic.

William Saletan in Slate on April 28, 2013 rounds up several stories that explore the possible explanations and motivations behind the radicalization of the suspects.

An April 23, 2013 Associated Press story says questioning of Dzhokhar Tsarnaev by authorities indicated “the two brothers were motivated by an anti-American, radical version of Islam.” A CNN story adds that the older brother was the driving force behind the attacks and that they had no contact with international terrorist groups but were affected by watching videos online.