Woman pleads not guilty to murder of City banker partner

Joanna Cierpka has pleaded not guilty to the murder of her partner, City banker Henrik Slotsaa, at the Old Bailey. The court heard on March 15, 2026, police discovered Mr Slotsaa, 52, dead at their home in Elephant and Castle. Officers had been alerted to welfare concerns at the property. They forced entry at 2.41pm and found Cierpka, 51, injured inside.

Mr Slotsaa, a Danish national who worked at Citibank’s London office, was found in a bedroom. It was clear he had been deceased for some time, the court was told by prosecuting barrister Danny Robinson KC. Cierpka, who is Polish, was arrested and taken to hospital for treatment. There, she made a written statement to a staff member, saying: “I killed my partner”. She signed and dated the note.

Defence claims diminished responsibility

Cierpka has admitted to manslaughter by reason of diminished responsibility. The defence claims she was suffering from severe depression at the time of the killing, which impaired her judgment and self-control. A psychiatrist instructed by the defence, Dr Penelope Brown, believes Cierpka experienced an abnormality of mental functioning arising from a recognised medical condition. This, according to Dr Brown, substantially impaired her ability to form rational judgments and exercise self-control, making the defence of diminished responsibility available.

The prosecution has presented evidence suggesting Mr Slotsaa had been involved with a colleague at Citibank. Friends of the couple, Stephen Lynn and Anna Kotynska-Lynn, testified about the relationship's deterioration. Mr Lynn stated that Mr Slotsaa had mentioned he was planning a life without Cierpka and had been “flirting” with a work colleague named Aimee O’Shaughnessy. Mr Slotsaa reportedly told Ms O’Shaughnessy in late 2025 that things were not good at home and that he liked her. She stated she did not want to start a relationship with him.

The prosecution has also obtained a report from a psychiatrist, Dr Shamir Patel, who was instructed to examine Cierpka. Dr Patel agreed that Cierpka was suffering from depression at the time of the killing. However, he did not accept that this condition substantially impaired her ability to form a rational judgment or exercise self-control. Dr Patel concluded that the killing occurred due to anger and jealousy towards Mr Slotsaa concerning his friendship with Ms O’Shaughnessy, against a backdrop of their relationship breakdown and Cierpka's alcohol use.

Details of the incident

A post-mortem examination conducted by forensic pathologist Dr Ashley Fegan-Earl on March 18, 2026, found 14 separate sharp force injuries. These included wounds to the face, neck, arms, and legs. Three neck injuries were potentially fatal on their own. Stab wounds to the right index finger and left forearm were considered defensive injuries. Wounds to the backs of both knees may have indicated an attempt at dismemberment, the prosecution stated.

The trial continues.