Monday saw Dzhokhar Tsarnaev charged with using a weapon of mass destruction, but officials aren't focused exclusively on the suspect in custody.
Katherine Russell Tsarnaev, the wife of deceased Boston bombing suspect Tamerlan Tsarnaev, is wanted for questioning by federal authorities.
The widow says she learned her husband and brother-in-law were the accused Boston Marathon bombers the same way as most Americans: on TV.
A lawyer for Katherine, also the mother of Tamerlan's 3-year-old daughter, Zahara, claims she had no clue her husband allegedly plotted the bombing.
Federal investigators visited the 24-year-old at her parents’ home in North Kingstown, R.I. Her attorney says she is “decidinh how we want to approach this.”
Tamerlan Tsarnaev, 26, died after a shootout with cops early Friday after officials say he and brother Dzhokhar Tsarnaev, 19, fatally shot an MIT officer.
Dzhokhar Tsarnaev, 19, remains in a Boston hospital, but is unable to speak - according to some sources, due to a self-inflicted throat wound.
Dzhokhar was somewhat miraculously captured alive and in custody Friday night after a massive, city-wide manhunt that lasted nearly 24 hours.
Authorities want to speak with Katherine as they are trying to piece together a motive, and whether the pair had ties to any Islamic terror cells.
The brothers, ethnic Chechens, left Russia with their family in 2002 and became legal residents of the U.S. Dzhokhar later became a U.S. citizen.
Investigators are focusing on the six months Tsarnaev spent last year in the predominantly Muslim provinces of Dagestan and Chechnya.
They want to know if he was radicalized by the militants in the area who have waged a low-level insurgency against Russian security forces for years.
The suspects’ parents moved back to Russia.