Death-penalty expert to defend bomb suspect

Tamerlan Tsarnaev, 26, died after a shootout with police. His younger brother, Dzhokhar, 19, sustained gunshot wounds and is being held at a prison medical facility west of Boston. He has been charged with using and conspiring to use a weapon of mass destruction resulting in death, as well as one count of malicious destruction of property by means of an explosive device resulting in death.

On Monday, a federal judge appointed prominent defense lawyer Judy Clarke to represent the wounded suspect, who could be sentenced to death if convicted.

Legal colleagues consider Clarke to be the nation's foremost expert on defending federal capital cases. She has represented numerous high-profile clients facing Death Row, including Ted Kaczynski, the Unabomber; Eric Rudolph, who admitted to the 1996 Atlanta Olympic bombing and other attacks; and Jared Lee Loughner, who pleaded guilty to killing six people and wounding 13, including then-U.S. Rep. Gabrielle Giffords, in a Tucson, Arizona, shooting spree. All of them are serving life in prison.

FBI enters suspect's widow's family home

Investigators moved forward on another front in Rhode Island, searching the family home of Tamerlan Tsarnaev's widow, Katherine Russell, for about 90 minutes on Monday.

Russell and her toddler daughter -- Tamerlan's child -- have been staying at the North Kingstown home with her parents. Her attorneys were present during the search.

Agents left the home with items that included a black case and a clear plastic bag identified as DNA samples.

A law enforcement official warned that even if Russell's DNA matches the female DNA on the pressure cooker, that does not necessarily prove she had anything to do with the preparation of the bomb. She -- or any other female -- might have come into contact with the cooker in the past.

Russell has said she was completely in the dark about her husband's alleged plan. Her attorney said the news "came as an absolute shock."

The two were married on June 21, 2010.

The double bombing near the finish line of the Boston Marathon killed three people and wounded more than 260. Twenty-three remained hospitalized on Monday. At least 14 people have needed amputations, according to medical officials.

Investigators searched a landfill in New Bedford, Massachusetts, in hopes of finding a laptop that could be relevant to the case. But the two-day effort ended without success, a U.S. law enforcement official told CNN Monday.

The FBI was following leads from Dzhokhar and others that his laptop was thrown in a dumpster and then picked up for disposal at a landfill.

The laptop might not be crucial to the investigation, the official added.

The suspects allegedly used low-grade explosives inside pressure cookers.

Investigators so far have found no evidence that the Tsarnaev brothers tested such bombs in the United States, the U.S. law enforcement official told CNN Monday.

If Tamerlan received training in making bombs, it may have come during his trip to Russia, the official said.

Sources: Russian forces kill two jihadists

Investigators are looking into whether Tsarnaev was influenced toward radicalization during a six-month visit in 2012 to Dagestan, a region known to include radical jihadists who have battled the Russian government.

Russian special forces killed two members of a jihadist group in an early morning raid this weekend in the semiautonomous republic, two Russian police sources told CNN on Monday.

Authorities have not said whether the raid was linked to the Boston bombing.

But one of those killed was an associate of Abu Dujan, the slain leader of a militant Islamist organization that produced at least one video that Tamerlan apparently posted and later removed from a social media account, according to an analysis by CNN and the SITE Intelligence Group.

'Jihad' discussed in wiretapped phone call

Russian authorities intercepted a phone call in early 2011 from one of the Tsarnaev brothers in the United States to their mother in Dagestan, an official with knowledge of the investigation told CNN over the weekend.