The singer's sister died due to a fatal combination of drugs described as "the perfect storm" by the coroner
Louis Tomlin and sister Félicité

Louis Tomlinson‘s 18-year-old sister Félicité died from an accidental overdose, a coroner has concluded.

The teenager died due to a fatal combination of drugs described as “the perfect storm” by Coroner Shirley Radcliffe, according to the BBC, who adds that traces of Xanax, OxyContin and cocaine were found in her system.

A rep for Tomlinson did not immediately respond to a request for comment from PEOPLE.

Before her sudden death, Félicité, who was also known as Fizzy, worked as a model and influencer with over one million followers on Instagram.

On March 13, she passed out after a suspected cardiac arrest at her studio apartment in Earls Court, West London, according to The Sun.

| Credit: Felicitie Tomlinson/Instagram

A friend, who was with Félicité at the time of the incident, immediately dialed 911, according to reports.

When emergency responders arrived to the home, they attempted to resuscitate Félicité; however, 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 previously 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.”

Tomlinson spoke out for the first time about his sister’s death in April, thanking his fans for their words of encouragement.

“Just wanted to thank everyone for their lovely words over the past couple of weeks,” the 27-year-old former One Direction singer shared on Twitter at the time. “Back in the studio today to vocal something I wrote a few months ago. Sending you all loads of love x.”

Félicité’s death came after their mother Johannah Deakin died of leukemia on Dec. 7, 2016. She was 43. Just weeks before his sister’s death, Louis paid tribute to his late mother in “Two of Us” — the first single off his debut solo album.

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The song is a deeply personal and emotional pop ballad about the bond the two shared even after her death.

It begins by Tomlinson addressing Deakin directly, admitting that the day she died he wished “it was me instead.” However, after mourning her loss, Tomlinson began to take the lessons he learned from her and focus on the positives.

“I will keep you day and night, here until the day I die / I’ll be living, one life for the two of us,” he sings in the chorus. “I will be best of me, always keep you next to me / I’ll be living one life for the two of us.”