A child actor from Brazil has died at the tender age of 11 after suffering multiple heart attacks related to a mystery illness.

The family of Millena Brandão, who made a name for herself in the Netflix series Sintonia, announced the tragic news on Sunday, May 4.

“Open letter to my little girl. On 02.05 we lost our baby girl, but I’m sure she’s in the arms of our Almighty Father and in a beautiful place to play,” their statement reads.

“The memories we spent together will remain in my memory and I will never forget your joy that spreads to everyone around you. My girl, I miss you not having you here and I know I will miss you even more in the days to come!”

It continued: “You were a light in our life and I know that from above you will continue to look over us and light up our lives.

“And I will love you forever, and you will always be in my heart.”

According to the Huffington Post, Millena had experienced excruciating headaches, leg pain, loss of consciousness and 13 cardiac arrests over several days. The 11-year-old’s mother, Thays Brandão, told Brazilian outlet G1 that doctors suspected dengue fever or perhaps a brain tumor but never determined the exact cause.

A mass was discovered later and will be biopsied, the outlet reported.

“She got worse, with two to three cardiac arrests per day. She had 13 arrests in total,” her mother told G1.

“She had never had that before. There was one day when she had seven respiratory arrests. Sometimes they gave her massages and other times they gave her shocks [with a device called a defibrillator].”

When Millena suffered cardiac arrest she was transferred from UPA Maria Antonieta to Granjaú General Hospital.

“There was no neurologist there. They only did a CT scan, and the doctors said they saw a 5-centimeter mass in her brain,” Thays explained.

“But they don’t know if this mass was a tumor, a cyst, an edema, a clot… because they couldn’t open her head to see. And now that she died, they’re going to do a biopsy to find out what was in her brain.”

Heartbreakingly, on Friday of last week (May 2) she was confirmed to be brain dead, and her parents consented to having the machines sustaining her life turned off, the mother explained. She passed away that same day.

Sintonia, the series in which child actor Millena made her name, has run for five seasons on Netflix.

Rest in peace, Millena Brandão.