Hospitalized Boston Bombing Suspect Says He And Brother Acted Alone, Motivated By Religion.

The hospitalized Boston Marathon bombing suspect charged Monday with using a weapon of mass destruction has told investigators that he and his brother were motivated by religion but were not in contact with overseas terrorists or groups, officials said.

Several officials familiar with the initial interrogation of Dzhokhar Tsarnaev described his behavior during questioning as cooperative.

A senior government official said Tsarnaev has told investigators — by writing some answers down, and by nodding yes or shaking his head no to others — that he and his brother were not in touch with any overseas terrorists or groups.

Tsarnaev, who has injuries to his tongue preventing him from speaking properly, also indicated that he and his brother conceived the bombing attack on their own, and were motivated by religious fervor.

They got their instructions on how to make bombs from the Internet, he said, according to these officials.

Earlier on Monday, the White House said he will be tried in a civilian court.

“He will not be treated as an enemy combatant. We will prosecute this terrorist through our civilian system of justice,” White House Press Secretary Jay Carney said.

“Under U.S. law, United States citizens cannot be tried in military commissions. And it is important to remember that since 9/11 we have used the federal court system to convict and incarcerate hundreds of terrorists.”

Tsarnaev, 19, a naturalized U.S. citizen of Chechen origin, made his initial court appearance at Beth Israel Deaconess Medical Center, where he was listed in serious condition.

He was advised of his rights and charged with one count of using and conspiring to use a weapon of mass destruction in the U.S. and one count of malicious destruction of property with an explosive device.

He was assigned three federal public defenders. The charges could carry the death penalty.

The suspect agreed to “voluntary detention,” but declined to answer questions about bail, according to a court record. A probable cause hearing was set for May 30.

“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 a statement.

“We will hold those who are responsible for these heinous acts accountable to the fullest extent of the law.”

A criminal complaint laid out some of the evidence against Tsarnaev, who was arrested Friday after a daylong manhunt, and his brother, Tamerlan, who was killed during a firefight with police.

A black jacket and white hat, matching the ones worn by “Suspect No. 2″ in surveillance video, were found in the younger brother’s dorm room, along with green strands of fuse like those used in the marathon explosives that killed three and wounded more than 170.

The video also captured the suspect making a cellphone call seconds before the first bomb exploded on the east end of Boylston St. during last Monday’s race, and his utter calm in the face of spreading panic, the complaint said. The footage showed him hurrying away from his knapsack just 10 seconds before a blast erupted where he left it.

Tsarnaev was brought to the hospital with gunshot wounds to the head, neck, leg and hand. He had been communicating with investigators in writing because he couldn’t speak, federal officials told NBC News.

The FBI has not officially revealed a motive for the attack last Monday that killed three people — one of whom, Krystle Campbell, was laid to rest in Medford on Monday. Investigators are still probing whether the brothers received assistance from others, officials said.