A woman who filmed herself killing a cat before putting the animal in a blender has been jailed for life for murdering a man four months later.

Scarlet Blake, 25, appeared at Oxford Crown Court on Monday after being found guilty of murder last week.

Warning: This story contains descriptions that readers may find distressing

Blake live-streamed the dissection of a family pet after watching a Netflix documentary called Don’t F*** With Cats, in which Luka Magnotta kills kittens before filming a murder.

Prosecutors said Blake, who is transgender, had a “fixation with violence” and found Jorge Martin Carreno, 30, while searching the streets of Oxford looking for someone to kill in the early hours of 25 July 2021.

Sentencing Mr Justice Chamberlain KC said Blake “had an obsession with harm and death”.

“The decision to kill was entirely yours,” he said, telling Blake, “you were completely indifferent to this suffering.”

Blake will serve a minimum term of 24 years in jail.

The body of the BMW factory worker, a Spanish national who was walking home alone after a night out with work colleagues, was found in the River Cherwell at Parson’s Pleasure around 24 hours later.

Her trial heard a murder investigation was launched two years later when Blake’s former partner Ashlynn Bell, who lives in the US, told detectives Blake had confessed to killing Mr Martin Carreno using a homemade garrote.

Blake pleaded guilty to a charge of criminal damage over killing the cat but denied murdering Mr Martin Carreno by inflicting blows to his head before trying to strangle him and then putting him in the river.

Four months before his death, she used food and a crate to capture a cat and take it to her home, where she killed it.

In the video, in which Blake dissects the animal, removing the fur and skin, she says: “Here we go my little friend. Oh boy, you smell like shit. I can’t wait to put through the blender.”

Prosecutors said it showed she had a “disturbing interest in what it would be like to harm a living creature”.

“It was an interest that went beyond mere fantasy,” Alison Morgan KC told jurors, who were also shown videos of Blake and a partner engaging in consensual strangulation with ligatures.

“She described herself to others as being someone who derived sexual gratification from the thought of violence and the thought of death,” said the prosecutor.

CCTV footage showed Mr Martin Carreno trying to find his way home, while Blake walked the streets, wearing a facemask and distinctive combat-style jacket with hood over her head, while carrying a rucksack.

“He died because he encountered the defendant on that night,” said Ms Morgan.

“He died because he met a person who had a fixation with violence and with knowing what it would feel like to kill someone.”

Blake, who was born in China and came to the UK aged nine, blamed Ms Bell for making her kill the cat.

She said Mr Martin Carreno was still alive when she left him at the riverbank, and that she had made up details of killing him to please her ex-partner after seeing his death in the news.

Mr Martin Carreno’s family paid tribute to “an extraordinary being full of passion and kindness” who was one of three triplet brothers.

“Today, his absence leaves a deep wound in our hearts,” they said in a statement. “His life was stolen, cutting short his projects and dreams.”

Mr Martin Carreno’s mother said her son “aspired to build a better world” and was an “incredibly good person”.