Michaela Kardeis, head of public security, told a news conference on March 13 that for now there were no more details about the 26-year-old assailant's background or possible motives.
Material seized at his home such as a computer and cellphone and his social media activities would be further analyzed in the coming days, Kardeis said.
Meanwhile, the Defense Ministry said that during his Austrian military service in 2012 the man was registered as a devout Muslim.
The Vienna-born man of Egyptian origin, named by police as Mohamed E., attacked the soldier outside the Iranian envoy's residence late on March 11, stabbing him several times with a knife.
Police said the soldier initially used pepper spray before opening fire on the assailant.
The guard suffered a wound to his upper arm.
The Kurier newspaper reported that the man, who lived with his parents in a working-class area of Vienna, followed a German Salafist preacher on Facebook.
He was also a fan of a Facebook group that agitated for the 'release of Sunni prisoners' in mostly Shi'ite Iran, it reported.
Salafists follow a strict form of Sunni Islam and do not recognize other branches of Islam, such as Shi'ism and Sufism.
Based on reporting by AP and AP