A woman accused of stabbing her partner to death in London will face trial in September. Henrik Slotsaa’s body was discovered at an address he shared with his partner, Joanna Cierpka, 51, in Newington Causeway, Elephant and Castle, in south London, on 16 March. Mr. Slotsaa, 52, had been stabbed multiple times and had been dead for some time when police broke down the door. Cierpka, originally from Gdynia, Poland, was taken to the hospital, where she told a staff member, “I killed my partner.” She appeared at the Old Bailey via video link from HMP Bronzefield wearing a grey t-shirt. Her next court appearance is scheduled for 15 July, with a trial set for 14 September. The trial has heard that Cierpka, accused of killing her boyfriend, had sent explicit messages to a waiter while on holiday in Greece. According to the court, Joanna Cierpka allegedly murdered Henrik Slotsaa in March after he told her on her birthday that he had met someone else at London’s Citibank office in Canary Wharf, where he worked. During the summer of 2025, jurors were told, Cierpka exchanged messages with a restaurant worker she called her “sweet boy.” In a series of Viber messages, she appeared to be discussing plans to meet with Dennis Leftakis after his shift. When Cierpka suggested he might need rest “instead of depressing old woman,” Mr. Leftakis responded, “No, don’t say that,” and told her he wanted to kiss and hug her. The next morning, she messaged him, asking how he was feeling and saying, “Hope I did not drain you dead.” He replied, “Alive, not dead but alive.” Later that day, after picking up Mr. Slotsaa at the airport, she messaged Mr. Leftakis again, saying, “Still feel you on and in me.” Before Mr. Slotsaa joined her in Greece, Cierpka had referred to him as “my Viking” in separate WhatsApp messages, the court was told. Cierpka was arrested after police found Mr. Slotsaa’s body at their home in Elephant and Castle, south London, on 15 March 2026, following concerns about his welfare. Prosecutor Danny Robinson KC informed the court about internet searches found on Cierpka’s phone in the days before Mr. Slotsaa’s body was discovered. On 19 February, Cierpka’s phone was used to search for the phrase “I don’t want to live anymore, how to end it,” the court was told. On 8 March, searches were made for “which artery bleeds the fastest” and how to find the aorta, femoral, and carotid arteries. The following day, Cierpka’s phone was used to look up the “highest penalty in the UK.” Polish national Cierpka has pleaded not guilty to murder but claims she is guilty of manslaughter by reason of diminished responsibility. The court has heard that Cierpka was made redundant, which affected her self-confidence, and she had previously received treatment and medication for depression. At the conclusion of the prosecution’s case, the Old Bailey trial was adjourned until Wednesday. The case will now proceed with the defense’s arguments, before the court decides on the next steps. The trial is expected to continue with further evidence and testimony in the coming weeks.