BOSTON, Mass. -

Accused Boston Marathon bomber Dzhokhar Tsarnaev has been charged with using a weapon of mass destruction against persons and in connection with the blasts that killed three and wounded at least 176 last week.

The charges were unsealed hours after Tsarnaev had his initial court appearance from his hospital bed.

The case being built against the 19-year-old college student includes one count of using a weapon of mass destruction resulting in death, and one count of malicious destruction of property. The Justice Department released a statement indicating that the charges could carry the death penalty or life in prison.

"Although our investigation is ongoing, today's charges bring a successful end to a tragic week for the city of Boston, and for our country," Attorney General Eric Holder said in the statement. "We will hold those who are responsible for these heinous acts accountable to the fullest extent of the law."

Law enforcement sources say Dzhokhar Tsarnaev, 19, was arraigned at his hospital bed, which was first reported byABC News affiliate WCVB.

Tsarnaev was awake and responding sporadically in writing to questions Sunday night. They are asking about any possible cell members and other unexploded bombs. There have been no additional details yet on his answers.

Tsarnaev is being treated at Beth Israel Deaconess Medical Center in Boston, where he is listed in serious but stable condition, with wounds to the neck and throat area, according to sources.

The arraignment occurred as Tsarnaev's parents have been defending their sons' innocence in interviews in Russia. The mother of the bombing suspects told ABC News she spoke to her eldest son minutes before a violent standoff with police in the streets of Watertown, Mass.

Tamerlan Tsarnaev, 26, called his mother early Friday morning, alerting her that police were following him and his younger brother and that there had been a shooting.

"'The police, they have started shooting at us, they are chasing us,'" Zubeidat Tsarnaeva told ABC News in a telephone interview.

The conversation ended when Tsarnaev said, "'Mama, I love you,'" his mother said.

Tsarnaeva got frightened and started to cry and shout. He told her Dzhokhar Tsarnaev, 19, was with him before the line cut off.

Her daughter called later to say that Tamerlan had been killed.

Last week's twin bombing killed three, including an 8-year-old boy, and wounded about 170. An MIT officer was allegedly killed by Tsarnaev and his older brother Tamerlan, and a Boston transit cop was badly wounded in a subsequent shootout.

New details emerged Sunday night about the dramatic capture after a 20-hour manhunt for Tsarnaev after he managed to escape a gunfight with police in Watertown, Mass., that killed his older brother.

As police and federal agents closed in after a Watertown resident reported there was a bloodied person hiding in his boat, a helicopter beamed back thermal images of the outline of Tsarnaev's body.

The orders went out to do everything to capture the teen alive even after an initial exchange of gunfire.

Police quickly surrounded the boat and there was a brief but ferocious volley of fire. Watertown Police Chief Edward Deveau told ABC News Sunday that negotiators demanded Tsarnaev show his hands and lift his shirt. Authorities were worried Tsarnaev was wearing a suicide vest. He was not.

"He was very slow and lethargic in every move that he made and they could see that there was no device on his chest. They kept creeping closer to him and then they felt it safe enough to pull him away from the boat," Deveau told ABC News' Martha Raddatz.

From that point, Tsarnaev was raced to Beth Israel Deaconess Medical Center, where investigators hope to get answers to questions about motive and the possibility of accomplices.

Nowhere were there more questions than at the University of Massachusetts Dartmouth, where Tsarniev was known as just an ordinary student.

"Literally, when I seen him he was just regular. He walked past me, we had a brief conversation and then I asked him for a ride home and he told me, 'Yeah,'" said Andrew Glasby, who lived at the same dormitory where Tsarnaev was staying after the marathon bombings.

Another friend, Zach Bettencourt, even asked Tsarnaev about the bombings.

"I talked to him in the gym about the bombing and he was like, 'Yeah man, tragedies happen all the time,'" Bettencourt said.

The night after the bombing, Tsarnaev tweeted, "I'm a stress free kind of guy."