(CNN) -- At least two of three additional suspects arrested Wednesday in the Boston Marathon bombing probe face obstruction of justice charges, a federal law enforcement source said.

Boston police announced the arrests Wednesday morning, adding that there was "no threat to the public."

Two students from New Bedford, Massachusetts, have been arrested on charges of making false statements to investigators and conspiracy to obstruct justice, according to a federal law enforcement source with firsthand knowledge of the investigation.

Alan Dershowitz, a prominent defense attorney and Harvard law professor, said the new charges don't appear to be related to the bombing itself.

"If they knew about the bombing, if they were involved in the bombing, the charges would be conspiracy to do the acts for which the other man has already been charged," Dershowitz told CNN. "So it sounds like at this point in time the only evidence they have is actions that took place after the bombing."

http://www.cnn.com/2013/05/01/us/boston-attack/index.html?hpt=hp_t1