Danish inventor Peter Madsen has been sentenced to life in prison without parole for the murder of the Swedish journalist Kim Wall on his submarine.
Madsen had planned to kill Ms Wall, 30, either by suffocating her or cutting her throat, the Copenhagen court heard.
Her dismembered remains were found by Danish police at sea on 21 August last year, 11 days after she interviewed him on board his homemade vessel.
Madsen, 47, has said he will appeal against the conviction.
He was found guilty of premeditated murder and sexual assault after previously admitting to dismembering Ms Wall's body on the submarine and throwing her remains overboard.
His claim that Ms Wall's death was accidental was dismissed by the court.
The case was heard by Copenhagen City Court Judge Anette Burkoe and two jurors.
Judge Burkoe said: "It is the court's assessment that the defendant killed Kim Wall.
"We are talking about a cynical and planned sexual assault and brutal murder of a random woman, who in connection with her journalistic work had accepted an offer to go sailing in the defendant's submarine."
She said Madsen had "failed to give trustworthy explanations" and had "shown an interest for the killing and maiming of people and has shown an interest for impaling".
Ms Wall had been researching a story about Madsen's venture and was last seen on the evening of 10 August as she departed with him on his self-built 40-tonne submarine, UC3 Nautilus, into waters off Copenhagen.
Her boyfriend raised the alarm the next day when she did not return from the trip. Madsen was rescued at sea after his submarine sank the same day. Police believe he deliberately scuttled the vessel.
Ms Wall's mutilated torso was spotted by a passing cyclist on 21 August but her head, legs and clothing, placed in weighted-down bags, were not discovered by police divers until 6 October.
After his arrest, Madsen gave differing accounts of what had happened on board his submarine.
During the opening session of his trial last month, prosecutors said there was a suspicion that he had "psychopathic tendencies" after investigators discovered films on his computer showing women being tortured and mutilated.
Madsen's shifting and unconvincing explanations helped convict him.
Initially, he said he had dropped Ms Wall off at about 22:30 the night before she disappeared and had not seen her since.
The next day Madsen gave police a new account of events, telling them there had been a "terrible accident" on board the self-built submarine.
Ms Wall, he said, had been accidentally hit on the head by the submarine's 70kg (150lb) hatch. He had then dumped her body somewhere in Koge Bay, about 50km (30 miles) south of Copenhagen.
On 30 October, police said the inventor had changed his story again and told them Ms Wall had died on board of carbon monoxide poisoning while he was up on deck. He also admitted dismembering her body, which he had previously denied.
After the verdict was announced, Madsen's lawyer Betina Hald Engmark told the court her client would appeal. He will remain in custody pending the process.