The suspect had uploaded an oath of allegiance to the current leader of the Islamic State group militia to an internet account a few weeks ago, investigators said Wednesday.
The Vienna Tourist Board is taking posts of nude and partially nude artwork found in the city's museums to a subscription service after content was removed from other social media sites.
The country's interior minister says the attack was carried out by an "Islamist terrorist" who was shot dead by police after a rampage through central Vienna.
