Peter Madsen, the Danish rocket scientist-turned-submarine engineer, sent a casual text message to his wife about 20 minutes after he dismembered Swedish journalist Kim Wall in his submarine’s bathroom. “I am on a little adventure with Nautilus,” he wrote, referring to the submarine he built himself. “Am sailing at sea by the moon, I am not diving. Kisses & hugs to the kittens.”

The message was read aloud in a courtroom in Copenhagen where Madsen is standing trial for murder, dismemberment and “sexual relations other than intercourse of a particularly dangerous nature.”

When Jakob Buch-Jepsen, the chief prosecutor in the case, asked Madsen how he had the composure to text his wife, the inventor said that at first he had thought he might take his own life, according to Robin Herr, a journalist who has been live-tweeting the trial highlights. But then Madsen worried he might miss his kittens. “I know that my wife would worry,” he said. “I couldn’t think of much else than that there was a catastrophe on the submarine.”

Madsen—who denies murdering Wall but admitted to dismembering the journalist’s body after stabbing her nearly 20 times around her pubic area—has changed his story several times.

When he was originally found outside his sunken submarine after putting out a distress call, he said he had left Wall at the harbor and had no idea what happened to her. Then, when her headless torso washed up on a nearby beach, Madsen said that in fact he had buried her at sea after the submarine’s hatch crushed her skull. After divers discovered her head and found there was no skull fracture, he said that he was mistaken, that instead she had died of toxic fumes when he had made a tactical error while she was in the hull and he was outside. Her limbs were discovered scattered across the seabed, weighted down with slabs of metal and pipes. The saw presumably used to cut up her body and her clothes were found in plastic bags weighted down with metal.

Madsen claims that after she died, he suffered “psychosis” and decided to “save her family” and get rid of her body by cutting it up in the submarine’s bathroom. “It’s something so horrible that I do not want to go into detail,” he told the court.

When pressed by the prosecutor to elaborate, he told the court that slicing her body was “an insane situation” that called to mind the 1995 horror film Se7en about a mad serial killer. When asked by the prosecutor if he didn’t find that an odd statement, he disagreed. “I don’t think that there’s anything unnatural in that remark,” Madsen said, according to press reports from the courtroom. “In that film, there is a scene where a person’s head is cut off.”

He then went on to confirm earlier testimony he had given to police, including how he had to leverage Wall’s body by sticking her legs into the submarine toilet while he sliced off her head. Madsen called it “very unpleasant and not planned.”

He then testified how he used a 19-inch sharpened screwdriver shown to him by the prosecutor to essentially skewer Wall’s body. “Yes, I put some punctures in the body parts because I didn’t want them to be inflated by gases,” he told the court, according to reporters who were in the courtroom. “There is nothing sexual in the fact that the stab wounds were in and near her vagina. I understand why you might want to think there was, but there was nothing sexual in it for me.”

Police also found ample evidence of his penchant for snuff films on his computer, including several animated Russian flicks showing beheadings and documentaries about serial killers. He had searched the internet for beheadings before Wall was killed. The judge and lay jury members were shown several films found on Madsen’s computer that were too disturbing to show the public audience. When asked about them, Madsen said that any relationship between the film searches and Wall’s death was “purely coincidental.”

Emma Sullivan, who was shooting a documentary about Madsen for Sky News, testified that he had told her in an interview not long before Wall was killed that he worried he might “be a psychopath.” He also made sexually explicit comments to her. “You should know what it’s like to have sex on the submarine, it’s amazing,” he said. Sullivan’s documentary will air later this year, now presumably with an ending about Wall’s murder.

Testimony earlier in the week by Madsen’s defense witnesses proved unhelpful, according to local press reports, which referred to it as a “defense implosion” whereby even those meant to testify about Madsen’s character couldn’t disagree he obsessed about murder and had often discussed snuff films and where to hide body parts and corpses.

The court also heard from a former “mistress” of Madsen’s who said he had belonged to several fetish clubs and that he had enjoyed risque sex. He had also described his ideal murder to her, which included a snuff film ending with a female victim dying on camera and friends joining him to dismember the body.

Danish coroner Christina Jacobsen told the court that while the exact cause of Wall’s death cannot be established from what is left of her body, they do have several plausible theories. “We think the airways were totally or partially cut off,” she told the court. “That would be due to either strangulation, throat cutting or drowning.”

Wall’s boyfriend, Ole Stobbe, told investigators that he nearly went with Wall on the submarine interview, but that Madsen had called at the last minute to set up an appointment on the very night the couple was having a quayside going-away party before moving to China.

According to an exposé for Wired magazine by Wall’s close friend, May Jeong, Stobbe apparently even waved to Wall across the harbor just minutes before the submarine went under. Jeong says that Wall told her boyfriend that she was “afraid to go on the trip in a submarine.”

The court also listened to Wall’s final texts to her boyfriend, which were likely meant as a joke, since she had told him she was concerned about going out alone with Madsen. “I’m still alive btw [by the way],” she texted not long after leaving shore. Then, just before the submarine submerged, she wrote, “But going down now!” and “I love you!!!!!!” Wall added that Madsen had brought coffee and cookies for the excursion. After that, she was never heard from again.

At the end of questioning on Thursday, the prosecutor asked Madsen about his childhood. “I wanted to be a victim in a child porn film,” the rocket scientist said, without further explanation.

The court will sit six more times before a verdict is expected at the end of April.