Danish submarine inventor Peter Madsen was found guilty Wednesday of torturing and murdering Swedish reporter Kim Wall before dismembering her body during a private submarine trip. He was sentenced to life in prison.

Copenhagen City Court Judge Anette Burkoe said she and two jurors unanimously decided Wall's death was a murder, finding Madsen also guilty of sexual assault and the defilement of a corpse.

"It is the court's assessment that the defendant killed Kim Wall," Burkoe told the packed courtroom.

During the 12 days of the trial that began March 8, the court heard testimony that Madsen lured 30-year-old Wall on to his hand-built submarine with the promise of an interview she had been trying to get for months.

Wall, a freelance journalist who wrote for leading magazines and newspapers, was last seen Aug. 10 waving to her boyfriend and other friends ashore as the submarine sailed off into the Baltic.

Her dismembered torso was found days later at sea off Copenhagen, and other body parts were found in plastic bags in October.

"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," Burkoe told the court.

Peter Madsen, the builder and captain of the private submarine UC3 Nautilus, was found guilty Wednesday of torturing and murdering Wall during a private submarine trip. He was given life in prison. (Bax Lindhardt/AFP/Getty Images)

"I am satisfied that the court has listened to what I said," prosecutor Jakob Buch-Jepsen told reporters outside court.

Madsen to be jailed through appeal process

Immediately after the verdict, Madsen's lawyer, Betina Hald Engmark, told the court she would appeal. The court ordered Madsen kept behind bars during the appeals process.

Throughout the trial Madsen denied murder, saying 30-year-old Wall died accidentally inside the submarine.

He changed his story several times. Initially he told authorities that he had dropped her off on shore and did not know what had happened to her. He then claimed she had died accidentally when hit in the head by the submarine's hatch. Finally, after her decapitated head was found by police divers in a weighted-down bag along with her appendages and the skull showed no signs of fracture, he said she had been asphyxiated in a malfunction aboard the submarine.

He also initially denied dismembering her, then confessed that he had done so and said he'd thrown her body parts into the Baltic Sea.

Burkoe noted the discrepancies, saying Madsen "failed to give trustworthy explanations." She added that evidence also showed he "has shown interest for killing and maiming of people and has shown interest for impaling."

Madsen listened quietly as the verdict was read, looking down at the desk in front of him.

Prosecutor Buch-Jepsen claimed Wall's murder was sexually motivated and premeditated because Madsen brought along tools he normally didn't take when sailing, including a saw and sharpened screwdrivers.

Madsen's defence lawyer had argued for his acquittal on the charge of murder, saying he should only be sentenced for the lesser charge of cutting Wall's body into pieces.

The cause of death has never been established but the court found that Madsen "cut the body into pieces to hide what had happened."

A life sentence in Denmark could mean a sentence as few as 16 years, depending on a parole decision.