Two men suspected of being involved in the Vienna attack on November 2 were arrested on Friday, the prosecution said on Sunday.
DNA traces of one of them, a 26-year-old Austrian of Afghan origin, were found on the murder weapons, according to a spokesperson contacted by AFP.
The prosecution refuses to “confirm the nationality of the second” suspect.
Requests for detention pending trial must be made during the day.
On November 2, four people aged between 21 and 44 were killed at close range in the Austrian capital.
A 20-year-old Austro-Macedonian claiming to be Islamic State was shot dead by police.
An association and a mosque which, according to the authorities, participated in its radicalization were dissolved and closed by order of the government.
Eighteen people have already been arrested shortly after the attack, in Austria and Switzerland.
Austria is a neutral country of 8.9 million inhabitants long spared from the jihadist threat.
It has identified the presence on its territory of about 150 jihadists.