"Words don’t even begin to describe how shocked and broken hearted we all are," Phoebe Tomlinson wrote on Instagram
Louis Tomlinson family is mourning the loss of their sibling Félicité, who died last Wednesday in her London apartment of a suspected cardiac arrest at the age of 18.
Félicité’s younger twin sisters Phoebe and Daisy Tomlinson both shared emotional written tributes to their late sibling on Instagram, each framed by a black and white childhood photo.
“Words don’t even begin to describe how shocked and broken hearted we all are,” Phoebe, 14, began her message. “You were my best friend, sister, motivator and person that could make me laugh until I cried. I’m lost without you and the thought of never seeing you again scares me like you wouldn’t believe.”
Later in their message, Phoebe referenced her late mother Johannah Deakin, who died after a battle with leukemia on Dec. 7, 2016 at the age of 43.
“Mummy needed you and you desperately needed her. I’m so glad your [sic] together now and she has you to rub her feet in heaven like you used to. I pray that you’re in a better place now. We love you like you wouldn’t believe.”
She concluded by writing, “Fly high my beautiful sister,” with an angel emoji.
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Daisy, also 14, shared her own message, accompanied by a vintage photo of all of her siblings together, in which she admits feeling in denial over the loss.
“No words will come close to explaining how broken I am, once again. My precious sister. My heart is bleeding. I keep imagining and praying they have the wrong person. Not my sister, my best friend,” she began.
“Mama needed you. i hope you are happier up there with her,” she concluded. “make sure you don’t forget about us. keep us in your conversations. i have two angels now, watching over me. i can’t wait to make you both so proud of me.”
On Wednesday, Félicité passed out after a suspected cardiac arrest at her studio apartment in Earls Court, West London, The Sun reports.
A friend, who was with Félicité at the time of the incident, immediately dialed 911.
When emergency responders arrived to the home they attempted to resuscitate Félicité; however, it was too late. She was pronounced dead at the scene, The Sun and The Daily Star report.
“Police were called by London Ambulance Service at 12:52hrs on Wednesday, 13 March to a residential address … following reports of a female in cardiac arrest,” the Metropolitan Police told PEOPLE in a statement. “Officers attended. A female believed to be aged 18 was pronounced dead at the scene. At this stage, the death is being treated as unexplained. A post-mortem examination will take place in due course. Enquiries continue.”
Before her sudden death, Félicité, who was also known as Fizzy, worked as a model and influencer with over one million followers on Instagram.
Her last post was on March 10. “Don’t know why I look so shocked,” Félicité captioned the shot, which shows her posing in a mirror wearing a black one-shoulder top and blue jeans.
Louis, 27, has not yet addressed his sister’s death publicly, though celebrity friends James Corden and Charlie Puth reached out via Twitter.
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A representative for the singer did not immediately respond to PEOPLE’s request for comment.
“Félicité was an absolutely adored young woman who was loved by Louis and her whole family,” a source close to the family told The Sun.
“They are totally devastated as you can imagine. She had so many friends and was such a positive happy person. It’s a massive loss to the world.”