Woman admits killing banker boyfriend after finding texts

Joanna Cierpka, 51, has pleaded not guilty to the murder of her City banker boyfriend Henrik Slotsaa, 52, but guilty to manslaughter by reason of diminished responsibility. Mr Slotsaa's body was discovered at their home in Elephant and Castle, south London, on March 15, 2026.

Giving evidence at the Old Bailey, Ms Cierpka told jurors her relationship with Mr Slotsaa and her mental health had deteriorated significantly. She stated that on her birthday in January, Mr Slotsaa told her he no longer loved her and had met someone else. Ms Cierpka described feeling sad after seeing text messages between Mr Slotsaa and the other woman on his phone, but felt unable to confront him.

Internet searches and relationship troubles

The court heard that on February 19, 2026, Ms Cierpka searched the internet for phrases including “I don’t want to live anymore” and “how to end it”. She also told the jury that days before Mr Slotsaa's death, she had looked up his female co-worker online out of curiosity about the person she believed she was being replaced by. When questioned about searching for “artery and neck”, Ms Cierpka stated her intention was to end her own life.

Ms Cierpka also told the court she did not know if Mr Slotsaa was alive or dead when she searched for “the highest penalty in the UK” in the early hours of March 9, 2026. She recalled going to the kitchen for a knife to kill herself, and her next memory was sitting in the living room with the blade on the coffee table. She stated she did not remember stabbing Mr Slotsaa in the bedroom or how he sustained injuries to the back of his knees, which were described as consistent with an attempt at dismemberment.

She told the jury she felt "mortified" as she had intended to be the one who was dead. Ms Cierpka explained her failure to call the police by saying: “I wanted to be dead before anyone found out.” She also stated that in the week before Mr Slotsaa's body was found, she had not changed her clothes.

Background and relationship breakdown

Originally from Poland, Ms Cierpka studied marketing and management and completed a master's degree in financial services before joining British American Tobacco. She met Mr Slotsaa through an online dating site, and they eventually shared a mortgage on their London flat. Ms Cierpka described their past as having an active social life with regular outings.

She found the coronavirus lockdown period particularly difficult. After being made redundant at the end of 2020, Ms Cierpka struggled with depression and job searches. She worked briefly as a barista at Starbucks in 2024 but did not secure permanent employment. Her relationship with Mr Slotsaa deteriorated alongside her mental health, and she described her life as a "daily battle with myself."

In 2025, Ms Cierpka had a five-week affair in Greece with Dennis Leftakis, who ran a taverna. She told the jury this "just happened" while she was feeling low, despite still loving Mr Slotsaa. She felt guilty about the affair but did not tell Mr Slotsaa, stating she did not want to break their relationship.

During cross-examination, Danny Robinson KC suggested Ms Cierpka had never told her partner about the affair. He highlighted that Mr Slotsaa had been straightforward about not loving her anymore and meeting someone else, and had still been trying to help her with her depression. Mr Robinson asserted that Ms Cierpka decided to kill Mr Slotsaa because she felt jealous after reading text exchanges between him and his co-worker, including a photograph.

The trial at the Old Bailey was adjourned until Thursday.