Educational authorities in the canton of St Gallen flagged up the 17-year-old for evaluation some four months ago, said news agency ATS.
In September the public prosecutor opened an investigation to assess whether the teen represented a risk to the public – and decided that he did not.
The boy had never expressed concrete threats towards anyone in particular, nor shown signs that suggested he would commit violent acts, therefore no concrete measures against him were imposed, reported ATS.
However according to Le Matin, the authorities didn't take into account the teen's page on Russian Facebook equivalent VKontakt, on which he wrote under ‘activities', “violence and killing children”, and stated Hitler's Mein Kampf as his favourite book.
But the St Gallen educational authorities denied there had been an error, telling the paper that, at the time the teen was assessed in September, he presented no threat to the public.
The 17-year-old was on Tuesday still in hospital after being injured during his arrest at a service station in Flums.
Police told the media that three of his seven victims also remained in hospital.
The rampage began on Sunday night at around 8pm when the Latvian, wielding an axe, set up on a couple walking with their baby in a pram on the Postplatz in Flums.
A 36-year-old man was seriously injured. The woman was also injured but the extent of those injuries has not been clarified, said ATS.
The baby was not attacked but fell from the pram during the fracas.
Two passers-by who came to help the couple were also injured – a 72-year-old man and a 59-year-old woman.
The teen attacker then fled in a car, which he promptly crashed. He then walked to a service station where he attacked three more people – women aged 21, 27 and 44.
Police then deployed tasers and guns to apprehend the perpetrator, injuring him in the process.
As yet the teen's motives are unknown. There is nothing to indicate a link to terrorism, said police.
Born in Latvia, the boy arrived in Switzerland four years ago and was pursuing an apprenticeship, said the media.
Friends told Blick he was quiet and “not the aggressive type”.