By Susanne Gargiulo and Judith Vonberg, CNN

(CNN) -- Danish inventor Peter Madsen has been found guilty of the mutilation and murder of Swedish journalist Kim Wall, and sentenced to life in prison.

Madsen was also found guilty of the indecent handling of a corpse and "sexual relations other than intercourse of a particularly dangerous nature," evidenced by stab wounds inside and outside Wall's genital area.

During the sentencing at a court in Copenhagen Wednesday, the judge Anette Burkoe described the crime as "a cynical and planned sexual murder of a severe brutal nature against a random women."

Wall, a promising 30-year-old journalist, was last seen boarding Madsen's self-built submarine in Copenhagen on August 10 last year when she had planned to interview him for an upcoming article.

Instead she disappeared, her torso washed up on August 21 on an island near Copenhagen. Her head and legs were found weeks later.

Madsen consistently denied charges of murder and sexual assault, claiming Wall died by accident from carbon dioxide poisoning, although he admitted to dismembering her body and tossing it into the sea in a state of panic.

Asked on Monday if he wanted to make a last statement before the jury went into deliberation, he said, "If anything, I am sorry about what happened." His attorney announced Wednesday that Madsen would be appealing the sentence.

The prosecution had asked for Madsen to be sentenced to life in prison or placed in "forvaring" -- a type of preventive custody with no time limit for prisoners believed to pose a significant danger to others.

Both are considered the harshest penalties in Danish law.

The question of forvaring or a life sentence arose based on Madsen's mental examination, which concluded that he remains dangerous, has psychotic traits, appears unfeeling and untrustworthy, suffers from lack of empathy and is highly sexually deviant.

Details of Wall's final night unclear

The brutality of this case has kept a global spotlight on the peaceful archipelago of Denmark since Wall's disappearance last year.

For most Danes, the prospect of Madsen walking free has become inconceivable. While many of them initially knew and supported Madsen as a mad, visionary and harmless inventor, that tide has turned. In the court of public opinion the verdict was in long before the trial began.

But many details of Wall's final night remain unclear and are likely to stay so unless Madsen chooses to share anything further.

Madsen's explanation that the journalist died accidentally from CO2 asphyxiation on board his self-built UC3 Nautilus was corroborated as plausible by one expert witness, and dismissed by another, making it difficult to prove either way.

It has also been impossible to determine Wall's cause of death, and while medical examiners say it is possible she died by strangulation, or by having her throat cut, results are inconclusive.

To prove his case, prosecutor Jakob Buch-Jepsen's strategy was to paint a picture of Madsen as a man motivated by dangerous sexual motives, who moved on the fringes of sadomasochistic societies and had an unusual interest in the killing and mutilation of women.

He presented a selection of more than 100 videos, cartoons and written texts found among Madsen's possessions, depicting the murder, torture and impaling of women -- in some cases real killings. The night before Wall's death, Madsen searched for and played on his phone a video of a girl having her throat slit.

Buch-Jepsen also focused on Madsen's shifting explanations, witness accounts and technical and forensic evidence. According to the medical examiners there were no signs that Wall died of CO2 poisoning, several of her cuts were unrelated to the amputations of her body parts and some were inflicted prior to or shortly after she died -- challenging Madsen's story that her body was intact until he dismembered her several hours after her death.

According to defense attorney Betina Hald Engmark, the prosecution's case was based mainly on circumstantial evidence, none of which proved Madsen committed murder. She told the court on Monday that Madsen should receive no more than six months in prison -- for the indecent handling of a corpse, for which he admitted guilt.