Convicted Islamic State sympathiser Kujtim Fejzulai killed four people before being shot dead by police in the city centre, the first major attack in Austria for decades and the first blamed on a jihadist.
The commission set up by the government in the aftermath of the attack had already delivered an interim report in December outlining several missed chances to spot the danger posed by Fejzulai.
That report found that it took far too long for a threat assessment to be carried out after Fejzulai was released from prison in late 2019 and that warnings about Fejzulai's activities from neighbouring countries were not acted on by the BVT.
Wednesday's final report says the BVT's responsibilities and those of its partner agencies in Austria's federal regions must “be rethought and more clearly defined”.
“The much-heralded restructuring of the BVT should be carried out transparently and without any further delays,” the report says.
The 29-page report also highlights the need for more efficient information sharing between services.
The report authors also write that “there must be a lasting improvement in the working atmosphere within and between services” and that “mistrust” in the agencies had to be addressed.
Some of the deterioration in the atmosphere in the BVT can be traced back to raids on the agency ordered by the Interior Minister Herbert Kickl of the far-right Freedom Party (FPOe) in 2018, the report says.
As for deradicalisation of those convicted of terror-related offences, which came under the spotlight following the attack, the report says that such programmes should be “professionalised, given a legal framework and the necessary financial resources”.
However, the report casts doubt on the efficacy of the government's plan to create a new offence of “religiously motivated extremism”, calling it “superfluous”.
Interior Minister Karl Nehammer welcomed the main findings of the report, telling journalists: “We must carry out reforms to build an efficient new structure, having learned from these mistakes.”
The report's authors said that some of their queries on whether certain terror-related warnings were passed to the upper echelons of the interior ministry “were not definitively answered”.
The opposition Social Democrats (SPOe) demanded “a complete and immediate clarification of what information the interior minister… had in the run-up to the attack”.
The SPOe maintained that the investigatory commission had “clearly been hindered in its work”, calling this “an absolute scandal which must have consequences”.