The man, who is in his 50s, is convicted of strangling the woman to death last November.
At the time, he had a temporary employment within the municipal elderly care in Strömstad, and it was during a home visit to the woman that the murder took place, according to the district court, which describes the act as "particularly ruthless".
The man is said to have filmed parts of the sequence of events and spread the film in a computer gaming group. When the police became aware of the murder several weeks later through the film, the woman had already been cremated, under the assumption that she had died a natural death.
Would never have been discovered
In the verdict, the district court states that the man strangled the woman in a way that left no visible traces and that the murder would likely never have been discovered if he had not revealed himself.
The remaining evidence includes, among other things, texts that contain descriptions of serious violent crimes and which, according to the prosecutor, show that the man had an interest in this for a longer period.
There is an interest in writing and taking part in stories about how people are tortured and killed and murdered, said prosecutor Daniel Veivo Pettersson to TT in connection with the conclusion of the trial.
"Was defenseless"
The district court states that the woman was defenseless.
"It must have been accompanied by a strong fear of death and severe suffering", it is written in a press release, and adds that this motivates the life sentence.
He is also to pay damages of 110,000 kronor each to the murdered woman's two children.
The man denies the murder. During the trial, he has confirmed that it was he who filmed the woman, but that this was on another occasion and that she did not die.
"The verdict will be appealed. Our opinion is that the district court has made an incorrect assessment of the evidence", writes the man's lawyer Elin Hagström in a written comment to TT.