“Self defence is what her lawyers are saying, but we have a different view on that, which I can't disclose,” said deputy chief prosecutor Ulf Back to daily Aftonbladet shortly after the incident.
The 49-year-old Wallin was found dead at the end of June in his house in Högbo, near Gävle in eastern Sweden. His 41-year-old girlfriend had alerted police and told them what had happened after returning back to her home in Södertälje, south of Stockholm.
After a rocky relationship followed by a brief separation, Wallin and his girlfriend had reunited, were moving in together at his new house and spending the midsummer celebrations there together with two of the woman's young children.
However, at some point during the night Wallin's arms were slashed by a blade and he was violently stabbed in the chest.
“He was subjected to ruthless violence,” said a police source to Aftonbladet at the time.
According to the girlfriend there was some violence prior to the incident, resulting in her grabbing the knife, which had been left on a table, so that Wallin wouldn't get to it first.
After the incident, the woman reportedly photographed Wallin's body and took her two children and left. Well back at home she called the police and told them of what had happened.
Police say that there is no clear motive to the murder but that the girlfriend's testimony indicates that a large amount of alcohol had been drunk over the course of the evening.
The forensic analysis shows that Wallin was lying down when he was stabbed and according to a witness statement the woman had given a detailed account of what she had done to a friend after returning home.
The friend said in interrogation that the woman told her how she had waited until Wallin was asleep before deciding where to stab him.
“We've spoken to that witness a number of times,” said Back to Aftonbladet.
The woman, however, claims that she stabbed Wallin in self-defence. She hasn't been able to explain why she took photos of his wounds an hour prior to leaving the house.
“I want to wait until I have heard the witnesses again before I say anything about the motive. Her version of events is not unambiguous,” Back told Aftonbladet.