Investigation continues

Boston bombing suspect communicates with police as details emerge about brother's past

Boston bombing suspect communicates with police

UPDATE: Federal authorities charged Dzhokar

Tsarnaev with using a “weapon of mass destruction” Monday afternoon. If convicted, the bombing suspect could face the death penalty, according to a statement from the U.S. Justice Department.

Suspected Boston bomber Dzhokar Tsarnaev — who was arrested Friday evening following a dramatic shoot-out in Watertown, Mass. — is conscious and sporadically communicating in writing, according to Monday news reports.

Unable to speak due to a severe throat injury, the 19-year-old has been questioned by investigators since Sunday about possible additional accomplices and other unexploded devices. He remains in custody at an area hospital in stable but serious condition.

As of Monday morning, Tsarnaev has not been charged in connection with the Boston Marathon bombings that took the lives of three and injured roughly 180. Authorities have yet to confirm what the suspect has revealed about the attacks.

Details continued to emerge about the recent high school graduate and his 26-year-old brother Tamerlan Tsarnaev — a boxer who was killed by gunfire early Friday during a police chase that left one MIT security officer dead and a transit cop wounded.

The brothers are no longer believed to be involved with a 7-Eleven robbery that occurred just prior to the manhunt.

Tamerlan Tsarnaev, Dagestan and the FBI

On Friday night, ABC News spoke with the suspects' mother Zubeidat Tsarnaeva via phone from Dagestan, the southwestern Russian republic where the Chechan family lived briefly before seeking asylum in the United States in 2002. The parents eventually would return to Dagestan, while the brothers stayed in the Boston area and continued their education.

Tsarnaeva said she her eldest son called her during the police chase, telling her he loved her and that Dzhokar was with him. The mother now fears that her 19-year-old son will receive the death penalty, a possible outcome as federal prosecutors led by U.S. Attorney General Eric Holder prepare to make charges early this week.

The mother also said that Tamerlan was investigated two years ago by the FBI only because "he loved Islam" and said he "didn't do anything bad." The FBI confirmed the 2011 investigation, which was sparked at the behest of an "foreign government" believed to be Russia, but noted in a Friday statement that he was found to have had no links to terrorist groups.

During the first half of 2012, Tamerlan Tsarnaeva traveled to Dagestan for six months. While his younger brother is a naturalized U.S. citizen, the older suspect was denied citizenship in Sept. 2012 due to the FBI investigation.

Investigators are attempting to interview Tamerlan Tsarnaeva's wife Katherine Russell, who worked as a home care aide while Tsarnaev stayed home to watch the couple's 2-year-old daughter. Russell's attorneys say she knew nothing of her husband's alleged involvement until seeing news accounts.

Boston Marathon bombing suspect Dzhokar Tsarnaev age 19 head shot
Dzhokar Tsarnaev
Boston suspect heat photography boat
Thermal imaging of Dzhokar Tsarnaev hiding inside a boat propped on a trailer in suburban Boston. Massachusetts State Police
Boston suspect arrested on ground
The 19-year-old was apprehended Friday night after a day-long manhunt that killed the suspect's older brother, also thought to be involved with the Boston bombings.