The revelations were made by Houston's longtime assistant Mary Jones in the documentary "Whitney (2018)", which debuted at the Cannes Film Festival last year (2018). And in an interview with People, the "Anyone Who Had a Heart" hitmaker insisted Dee Dee, also a singer, was innocent, and added she would never "forgive" her accusers.
"All I can say about Dee Dee is that she was a loving, caring, giving person," Warwick said of her sister, who died in 2008. "What was depicted of her is absolutely untrue and something I will never forgive."
In the documentary, directed by Kevin Macdonald, Jones claimed Houston had revealed to her that she was molested by her then adult relative when she was a child. Houston's assistant insisted it had had a negative impact on the singer, who was found dead aged 48 in a bathtub at The Beverly Hilton hotel in February 2012. She had accidentally drowned in the bathtub, with heart disease and her drug use cited as factors.
When asked about Houston in the interview, Warwick maintained, "I usually don't talk about her."
The "I Will Always Love You" singer had never publicly spoken about being abused prior to her death. However, in the documentary, her brother Gary also alleged a female relative had molested him when he was a child, as well as his superstar sister.
Meanwhile, Houston's mother Cissy said in a statement last year that she had never heard the allegations and that no one involved was alive to "deny, refute or affirm" the charges.
"Neither I, Dionne, nor my son Michael who was very close to his sister ... has ever heard these allegations; we have never heard anything remotely connected to the crimes charged against Dee Dee in the film," she said.