The family of a Greek heiress found dead just hours after being discharged from an NHS hospital following treatment for a suspected “toxic insect bite” is demanding accountability one year after her death.
Marissa Lemos, 30, was found in bed by a housekeeper at the family’s townhouse in Knightsbridge, central London, on September 11 last year. She lived there with her mother and father, shipping tycoon Diamantis Lemos.
Two days earlier, Marissa had been bitten by an insect. After developing itching, dizziness, a high temperature and symptoms of infection, she sought treatment at a private hospital on London’s Harley Street.
Her condition deteriorated, and Marissa—who had recently recovered from breast cancer—was taken by ambulance to the accident and emergency department at University College London Hospital (UCLH) on September 10, 2025.
Her family claims she was discharged without being examined by an NHS doctor and was assessed only by trainee medics. In one of her final messages to a friend, she wrote: “Nobody is checking up on me, nobody is coming.”
Marissa arrived home at about 8pm, took the antibiotics she had been prescribed and went to bed. The next afternoon, a housekeeper discovered her body.
The Lemos family, one of Greece’s most prominent shipping dynasties, has described a year of anguish to Our News Outlet. Relatives say they intend to pursue legal action over alleged clinical negligence.
Marissa’s parents, Bessy and shipping magnate Diamantis Lemos, were initially told that her symptoms were consistent with the “toxic effect of venom” from an “animal or insect bite”.
Yet as the family gathered in Athens last Friday for an emotional memorial marking the anniversary of her death, they said they still had no official cause of death—or an explanation for why she was discharged despite appearing so unwell.
Speaking exclusively to Our News Outlet, Marissa’s mother said: “We are very frustrated. It is heartbreaking. We cannot believe we are in the UK in 2026 and no one can tell us how our daughter died when she was hospitalised just a few hours before her death.
“We will never have peace unless we learn the cause of her death and who is responsible for this catastrophic outcome.
“We have been left in the dark and the system needs to change. My husband hopes other people like Marissa can be saved. But I have lost my child. Can I bring her back? No—and we are still waiting.”
Marissa Lemos, 30, was found dead by a housekeeper at the family’s London townhouse on September 11 last year.
Marissa is pictured with her mother, Bessy, and father, Diamantis. The Lemos family comes from a powerful Greek shipping dynasty.
Bessy Lemos said the family had been seeking answers “since day one”. Nearly two weeks passed before a post-mortem examination was carried out.
The delay forced the family to postpone Marissa’s funeral and burial in Athens.
After waiting a year for the post-mortem findings, relatives were told that the cause of Marissa’s death could not be established.
The family says it has still not received a copy of the results, despite repeated requests made through its lawyers.
They are also waiting for toxicology results, which they were told had been completed on June 25 this year.
The Metropolitan Police has since informed the family that further microbiology testing is needed and that a specialist must interpret the findings. The coroner will then decide whether an inquest should take place.
‘We have been very angry and furious since day one, since Marissa left the world,’ Ms Lemos said.
‘It is totally unacceptable and outrageous. We cannot believe this has happened.
‘They should have kept her that night. After all these tests, we are here today after a year and we still don’t know the cause of her death.
‘What would have happened if Marissa could have stayed on that night at the hospital? Obviously she would have been saved.’
The family marked Marissa’s one-year anniversary with a memorial service where she is buried in Athens last Friday.
‘We were looking at her grave thinking this is totally appalling and unbelievable what has happened to us,’ Ms Lemos said.
‘She did everything by the book. She didn’t stay helpless in her house and not asking for help. She went there in order for the people with the expertise to deal with it and they did nothing.
‘They just did some tests and let her go. A few hours later, she passed away.’
Marissa, a theatre actress, was born and raised in London, living with her parents at their townhouse in Knightsbridge.
She had recently returned to the capital after a summer holiday with her family on the Greek resort island of Porto Cheli, where she was ‘perfectly alright’.
But she began feeling unwell on September 9, 2025, developing dizziness, itching, a high temperature and other signs of infection, which proceeded to get worse in the night.
The family say Marissa called an ambulance and a doctor recorded a high fever of 39.1C but she decided to stay at home and said she would seek further medical attention if she did not feel well the next day.
But by the next morning, she had deteriorated so she took herself to the Leaders in Oncology Care (LOC), on London’s famous Harley Street, where she felt ‘very safe’ as she had previously been treated there for chemotherapy.
Medics carried out blood tests, gave her an antibiotics drip and antihistamine medicine. But due to the seriousness of her condition, they made the decision to call an ambulance to take her to UCLH.
It was here that trainees, rather than doctors, carried out blood tests on her and concluded that she did not need to be kept in hospital.
After her tests, Marissa’s family say she was discharged at 6.30pm and given antibiotics to take home with her, but she still felt seriously unwell and could not eat anything.
She would tragically go to sleep that night and never wake up again, with the family housekeeper finding her in her bed on September 11.
Marissa grew up in a Knightsbridge townhouse with her twin brothers, who are 26.
Pictured: Marissa with her twin brothers, mother Bessy and father Diamantis before her tragic death
Marissa is pictured with her mother Bessy as a young girl. Her mother is heartbroken by her daughter’s death
Marissa Lemos was a theatre actress and had starred in her own production of Romeo and Juliet
Her family were abroad at the time of her death and rushed straight to London when they were informed of the devastating news.
Her father, Diamantis, is part of the wealthy Lemos family who are one of the best known names in Greek shipping, with business roots stretching back to the early 20th century.
Despite being born into astonishing wealth, Marissa was keen to carve her own life, working in nurseries and as a receptionist at the Holiday Inn Bloomsbury while also juggling her real passion, theatre.
Although she was born and raised in the capital, she studied musical theatre in New York before going to the University of Arizona.
She had moved back to London in 2018 and credited her grandmother and friends ‘for always believing in her and pursuing her dreams’.
‘Marissa was a talented, beautiful young woman who had dreams and passions she had carried with her since she was a little girl,’ Ms Lemos said.
‘Above all, her greatest love was theatre.’
She had recently starred as Juliet in her production of Romeo and Juliet in London and was preparing to direct Oliver! with a cast she had chosen.
Before her sudden death, Marissa had battled through breast cancer. She was diagnosed in April 2023 and had to go through six months of ‘aggressive chemotherapy’.
After an operation, she was forced to spend four weeks in intensive care with hemophagocytic lymphohistiocytosis (HLH), an extremely rare condition where the body’s immune system does not work normally.
She had incredibly overcome her health battles and was enjoying her life again before tragedy struck.
Her devastated mother said: ‘After everything she had been through, including her battle with cancer and the difficult treatment that followed, Marissa did not give up on her dreams. Quite the opposite, she became determined to pursue them with even greater passion.
‘Marissa will always be remembered by those who knew and loved her for her extraordinary spirit, her kindness, her creativity and her determination to follow her passions.
‘She had a whole life ahead of her. She had so much more to give. And she should still be here.’
The Inner West London Coroner’s Court has been contacted for comment.
They previously said: ‘The case for Miss Lemos is still under investigation with the coroner’s office.’
A UCLH spokesperson said: ‘We offer our deepest condolences to Marissa’s family and remain open to meeting with them to talk about her care.
‘The results of the post-mortem have not been shared with us but we are ready to provide any information required from the coroner’s court.’
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