14-year-old Anais Fournier died last December, the official cause of death being "cardiac arrhythmia due to caffeine toxicity."
The teenage girl had a common heart defect but her mother, Wendy Crossland, filed a lawsuit saying Monster Energy failed to warn about the risks of consuming the energy drink.
Just 24 hours before the girl went into a coma and died, she drank two large cans of Monster.
Each one of those cans contains 240-milligrams of caffeine, which is the same as seven 12-ounce sodas.
The company says their product is safe to drink and not the cause of Fournier's death.
The FDA continues their investigation, and in total is looking at five cases of people who died after apparently drinking Monster Energy.
It's unclear whether any of the other incidents involved alcohol or other factors that could have contributed to the deaths.