The incident happened in May 2017 at the Stensjön lake in Grycksbo, near Falun.
According to the indictment, which The Local has seen, the victim was "killed by cutting or stabbing with scissors in his neck" and "died from bleeding as a result of the vascular injuries to his throat".
The prosecutor argues that the attack was carried out with intent, and the victim's wife said it was the result of a family conflict. She claims the suspect took offence to her and the victim's daughters shaking hands with boys, damaging the family's honour in his eyes, and the older relative then asked the father to kill them.
The father refused and ended contact with his relative. His wife believes he was subsequently lured to the lake where he was killed.
The suspect denies committing murder however and says he was assaulted by the father then used the scissors to defend himself.
Nine witness interviews, forensic evidence including blood samples, and analysis of the alcohol in the suspect’s bloodstream are among the evidence used in the investigation.
Later on Thursday it emerged that both the victim and suspect in the current case are relatives of Fadime Sahindal, who in 2002 was murdered by her father following her speech at the Riksdag about honour culture and oppression at the hands of male relatives. It is one of the most high-profile cases of honour killing in Sweden.
In May, one of her other relatives was sentenced to life in prison for the murder of his ex wife's partner.
In July meanwhile, six people were convicted of murder by Gävle District Court in a major honour violence case involving the work of around 100 police officers, where a man was killed after having an affair with a married woman.
Five were sentenced to life in prison while the sixth was sentenced to 14 years due to being under the age of 21 when the crime took place.