Story highlights Boston bomb suspect Dzhokhar Tsarnaev is no longer talking with investigators

Sources: A deal could allow him to avoid the death penalty if he resumes providing information

The talks are not a sign Tsarnaev's attorneys are ready to make a deal, one source says

High-profile attorney Judy Clarke has been added to the defense team

Some very preliminary talks have been under way "for the past few days" to potentially allow Boston bomb suspect Dzhokhar Tsarnaev to resume providing investigators with information about the attacks in exchange for having the death penalty taken off the table, two government sources say.

The sources said such initial communications between opposing sides on a range of procedural and other issues are standard procedure.

Communications are in the very early stages, and not a sign lawyers for either side are ready to make a deal, said one source, who did not want to be identified because of the sensitive nature of the private discussions. The source emphasized these are not formal negotiations, and no deals have been offered.

The discussions between prosecution and defense attorneys are at a "preliminary, delicate stage" and both refused to offer details of what either side would be willing to leverage, according to the sources. A Justice Department official said it is not accurate to suggest there are negotiations.

"The notion that we are engaging in discussions over a penalty is not accurate," the official said. "As far as I know, there are no negotiations."

The government has not said whether it will seek the death penalty in this case.

Justice Department spokesman Dean Boyd noted Tuesday that "the federal charges against Tsarnaev authorize a penalty, upon conviction, of death or imprisonment for life, or any term of years." The charges include using a weapon of mass destruction.

JUST WATCHED Who's the source of the 'female DNA'? Replay More Videos ... MUST WATCH Who's the source of the 'female DNA'? 03:09

JUST WATCHED See bombing suspect play with niece Replay More Videos ... MUST WATCH See bombing suspect play with niece 01:05

From fear to cheers: The final hours that paralyzed Boston

"We have no comment at this time on what potential penalty the government might seek if the defendant is convicted, particularly given that the defendant has only just been charged," Boyd added.

This comes after a federal magistrate judge Monday approved appointment of a defense attorney who specializes in handling capital cases. Judy Clarke of San Diego has a reputation of working with high-profile clients to get death-eligible crimes reduced.

She has represented Unabomber Ted Kaczynski, Atlanta Olympic bomber Eric Rudolph, and most recently Tucson mass shooter Jared Lee Loughner. Clarke separately cut deals for all three to avoid lethal injection.

The suspect is hospitalized with gunshot wounds at a federal Bureau of Prisons medical center in Devens, Massachusetts.

He and his brother, Tamerlan , are suspected of detonating two explosive devices at the Boston Marathon race April 15, leaving three dead and more than 175 people wounded. The elder Tsarnaev was killed three days later in a gun battle with police.

Legal sources say it is not unusual for both sides to reach out and begin these kinds of conversations in high-profile criminal cases. Those sources say both Tsarnaev's legal team and top-level Justice Department officials also have been meeting separately to weigh their options.

Two federal public defenders in Boston -- William Fick and Miriam Conrad -- were in the hospital room April 22 when Tsarnaev had his first court appearance, and had his Miranda rights first read to him by federal Magistrate Marianne Bowler. Those lawyers had asked for Clarke to join the legal team, and they must decide whether their client will cooperate with the ongoing investigation.

Tsarnaev's lawyers must weigh the initial evidence the government has presented against their client, and the strength of any additional charges that may be added when a formal indictment is presented in coming weeks. That evidence and Tsarnaev's own private statements about his alleged involvement will shape whether plea negotiations develop over time.

On the other side, government sources say investigators are eager to resume questioning of Tsarnaev, for any details about other possible suspects and plots. What may have motivated the brothers to allegedly commit the terror acts is also of major interest to the U.S. intelligence community.

Removing execution as a legal option could induce the suspect to talk, but nothing is expected until a grand jury hands down an indictment. U.S. Attorney General Eric Holder would have the final say on whether prosecutors would pursue the death penalty at trial. That decision, too, is some weeks off, said another government source.

A special team of federal agents were able to speak with the seriously wounded Tsarnaev for about two days without any Miranda warnings being given, under a "public safety exception." CNN has learned the young man admitted to the acts, and said he and his brother acted alone. Sources say he has since stopped talking with the government.