Federal authorities, however, dropped an inquiry into the matter after deciding that the messages from the psychiatrist, Major Nidal Malik Hasan, did not suggest any threat of violence and concluding that no further action was warranted, government officials said.
Hasan's 10 to 20 messages to Anwar al-Awlaki, a cleric, indicate that the troubled military psychiatrist came to the attention of the authorities long before shooting rampage at Fort Hood, but that the authorities left him in his post.
Counter-terrorism and military officials said that the communications, first intercepted last Dec 2008 as part of an unrelated investigation, were consistent with a research project the psychiatrist was then conducting at Walter Reed Army Medical Center in Washington on post-traumatic stress disorder.
"There was no indication that Major Hasan was planning an imminent attack at all, or that he was directed to do anything," one senior investigator said.
He and the other officials spoke on the condition of anonymity, saying the case was under investigation.