WASHINGTON — Nearly a year before Maj. Nidal Hasan allegedly went on a shooting rampage at Fort Hood, terrorism investigators conducted an "assessment" of him before deciding he did not pose a threat.

After the shooting, the FBI is doing a new assessment — of its own conduct.

The Army psychiatrist is believed to have acted alone despite repeated communications — intercepted by authorities — with a radical imam overseas, U.S. officials said Monday. The FBI will conduct an internal review to see whether it mishandled early information about the man accused in the bloody rampage that killed 13 people and wounded 29.

President Barack Obama was joining grieving families and comrades of the victims Tuesday at a memorial service at the sprawling Texas Army base. Hasan, awake and talking to doctors, met his lawyer Monday in the San Antonio hospital where he is recovering, under guard, from gunshot wounds in the assault.

In Washington, an investigative official and a Republican lawmaker said Hasan had communicated 10 to 20 times with Anwar al-Awlaki, an imam released from a Yemeni jail last year who has used his personal Web site to encourage Muslims across the world to kill U.S. troops in Iraq. Despite that, no formal investigation was opened into Hasan, they said.

Investigative officials spoke on condition of anonymity because they were not authorized to discuss the case. Republican Rep. Pete Hoekstra of Michigan, the top Republican on the House Intelligence Committee, said it was his understanding Hasan and the imam exchanged e-mails that counterterrorism officials picked up.

Officials said Hasan will be tried in a military court, not a civilian one, a choice that suggests his alleged actions are not thought to have emanated from a terrorist organization.

Meanwhile, The Washington Post reported Tuesday that Hasan warned his medical colleagues a year and a half ago that to "decrease adverse events" the U.S. military should allow Muslim soldiers to be released as conscientious objectors instead of fighting in wars against other Muslims. Hasan, an Army psychiatrist, made the recommendation in a culminating presentation to senior Army doctors at Walter Reed Medical Center, where he spent six years as an intern, resident and fellow before being transferred to Fort Hood.

"It's getting harder and harder for Muslims in the service to morally justify being in a military that seems constantly engaged against fellow Muslims," Hasan said in the presentation, a copy of which was obtained by the Post.