Your trusted source

Russia withheld details from U.S. officials about suspicions of Boston Marathon bombings suspect Tamerlan Tsarnaev in 2011, information that could have altered the course authorities followed, a U.S. law enforcement official told CNN.

The Wall Street Journal first reported Friday that while Russia did alert U.S. authorities about Tsarnaev's possible extremism, it kept out some facts, namely text messages referencing his desire to join a militant group.

However, sources told the paper that the United States also likely would have withheld such details for fear of divulging intelligence sources and methods.

In the texts, Tsarnaev wrote to his mother about his interest in joining the militant movement carrying out attacks against Russia in the Caucasus region, the law enforcement source told CNN.

The Russians did not pass these texts on to American officials when they passed the original intelligence about Tsarnaev, the source said.

The source was not clear on when those texts were eventually handed over.

House Intelligence Committee Chairman Mike Rogers, R-MIchigan, told the Wall Street Journal that the withheld information could have changed the way U.S. officials worked.