Jonbenets sister, Adrienne Ramsey, has been declared dead at age 84.
Ramsey, the third of four children, was found unresponsive in her home on December 29, 1996, after her mother reported her missing.
She was found by her brother, who had gone out to find her.
Her mother had been diagnosed with schizophrenia.
She had been hospitalized in New York and given a drug called phenobarbital, which can be fatal.
She had died three weeks later.
The coronavirus had spread throughout the United States and other countries.
Her death, along with that of a woman, Amy Ramsey, who died in 2011 at age 86, sparked nationwide outrage and prompted a coronavision to be performed on her in May 2000.
Ramseys family has said she was being treated at a psychiatric hospital for depression.
Her sister, who has been described as a sweet and loving woman, has become an icon of the cause of mental health and research.
She has been dubbed the “Queen of Science” for her research on the virus.
She was a professor of neurology at the University of Pittsburgh School of Medicine and received an honorary doctorate from the University College London in 2006.