Rättsmedicinalverket, the national forensic medicine agency tasked with examining suspects linked to Swedish crimes, has concluded that the man had mental health problems, according to reports in Swedish newspapers.
The move could mean that if he is found guilty, he will likely be sent for medical treatment rather than given a jail sentence.
The GT newspaper, which broke the news, said the findings followed its own investigations which suggested that staff at the refugee home he lived at in Mölndal in western Sweden had identified and reported the teenager's psychiatric problems before he attacked staff member Alexandra Mezher last month.
"I know that we sought help and we did that on several occasions," the paper quotes Staffan Andersson, the home's director, as saying days after Mezher's death.
A spokesperson for Rättsmedicinalverket confirmed to The Local that it had completed its report on the man's mental health but would not give any further analysis to the media.
"Usually we don't comment on our investigations," said press secretary Helena Norman.
The next public court hearing in the case is set to take place in Gothenburg on February 25th.
Last week, Sweden's Migration Agency revealed that the suspect was likely to be at least 18 years old, contradicting earlier reports that he was 15.
The asylum accommodation where he was living was a centre for unaccompanied refugee children. However, Johanna Måhlen, a press spokesperson for the agency told The Local that "the applicant did not make it probable that he was under 18 when he applied for asylum in the Nordic nation", despite ending up at accommodation for minors.