German investigators have searched the homes of two people linked to the perpetrator of November's terror attack in Vienna.
The two suspects belonged to the radical Islamist movement and were identified as relatives of the attacker, prosecutors said.
Authorities raided their homes on Wednesday, but no arrests were confirmed.
The searches, involving special forces, took place in the western district of Osnabrück and the central district of Kassel.
The two men, a German and a Kosovar, are accused of having been aware of the plans for the terror attack in the centre of the Austrian capital city, which killed four people.
The perpetrator --Kujtim Fejzulai, a 20-year-old Austrian who also held North Macedonian nationality -- was killed by police at the scene. He was known to the police after having tried to join the ranks of jihadist fighters in Syria.
Authorities said the two suspects were "in close contact" with the perpetrator "via social networks".
The prosecutor's office also said the two men had gone to Vienna to visit the attacker for several days in July last year, spending the night at his apartment.
"They met other people from the Islamist movement in Austria and Switzerland," a statement added.
Authorities also said DNA belonging to the two men was found on the weapons used in the attack, and that the group "shared radical Islamic convictions".
The two men had reportedly also deleted some of the messages they had exchanged with the attacker to cover up their connections.
A total of fifteen people have so far been arrested from the attack in Vienna.
Austria has acknowledged that "intolerable mistakes were made" in the handling of intelligence on Fejzulai, who had been released from prison less than a year earlier.