Family of the pop icon, who died on February 11, always believed her death was an accident and not down to deliberate action by Houston or anyone else.
While the cause of death is temporarily listed on Houston’s death certificate as “deferred” pending toxicology test results, “nothing suspicious” has been found.
The insider said: “She had no marks on her body whatsoever to indicate a struggle, and she was the furthest thing from trying to kill herself.”
Houston’s official cause of death is expected to be released in about a week, when toxicology results come through.
Sources say Houston had prescriptions for antidepressants and anti-anxiety medications and a handful of pill bottles were found in her room at the Beverly Hilton.
Houston was found dead in her Beverley Hilton bathtub, age 48, with her face underwater.
It was initially believed that the singer had drowned after falling asleep from taking a mixture of prescription pills and alcohol, but a small amount of water was found in her lungs.