Hasan, the alleged perpetrator of last week's fatal shootings in Fort Hood, TX, was charged Thursday with 13 counts of premeditated murder under Article 118 of the Uniform Code of Military Justice, which can carry a sentence up to death or life imprisonment.
The cards make no mention of his military affiliation, but underneath his name he listed himself as SoA (SWT). SoA is commonly used on jihadist Web sites as the acronym for Soldier of Allah, according to investigators and experts who have studied such sites. SWT is commonly used by Muslims as an acronym for Subhanahu Wa Ta'ala, Glory to God.
"He was making no secret of allegiances," said former FBI agent Brad Garrett, an ABC News consultant.
"It's one more piece of evidence that might have come out if investigators had taken a hard look at Hasan," said Garrett. "It doesn't say he's about to go out and shoot a bunch of people, but there's something not quite right for an Army major to self-identify that way."
The green and white business cards include the title Behavior Heatlh (sic) Mental Health and Life Skills.
Hasan listed a Maryland area mobile phone number and an aol.com e-mail address.
U.S. officials and analysts told ABCNews.com today that Hasan used multiple e-mail addresses and screen names as he contacted several jihadist web sites around the world.
On Hasan's official Army personnel record, obtained by ABCNews.com., Hasan lists his e-mail address using the first name of Abduwall, instead of Nidal. Abduwalli, in Arabic, means "slave of" the great protector, or God.