The woman's brother was able to identify the 53-year-old from Graz after seeing a photograph of her. The siblings were not close but he had planned to meet her on Sunday, and contacted the police when she didn't turn up.
As she didn't have a mobile phone and wasn't answering her door he was able to get hold of a key to her apartment and entered her home on Tuesday evening - but found no sign that she had been home recently.
When he contacted the police they showed him a photo of a woman they had been trying to identify, who had been killed in front of the parish church. He confirmed that it was his sister.
Police had thought she was around 35-years-old but despite appeals nobody had been able to identify her until now. Her brother said that she was very reclusive and had few friends. There had been some speculation that she was a tourist or a beggar, as no one had reported her as missing.
Three people died and 36 were injured after Alen R. deliberately drove his car at high speed into crowds of shoppers on a Saturday in mid-June. One of his victims is still in a critical condition in hospital.
Alen R. is being held in custody in Graz.