Young Hollywood is mourning the death of yet another troubled celebrity. Johnson and Johnson heiress Casey Johnson was found dead on Monday just weeks after actress Brittany Murphy passed away. Although no cause of death has been determined, many people are already speculating that the hard-partying heiress died of a prescription pill overdose. But it appears it may not be such an open-and-shut case. It's well known that Johnson suffered from diabetes and had fallen into a diabetic coma on at least two occasions. At least one of those incidents was last year. TMZ is reporting that medical personnel did find insulin syringes in her house. An autopsy is set to be conducted today, although Johnson's fiancée Tila Tequila told Radaronline.com she suspects the hard-partying heiress succumbed to a prescription pill overdose. Johnson had been in and out of rehab. The Johnson family issued the following statement, "The Johnson family is mourning its tragic loss, and asks for privacy during this very difficult time." However, Tequila released her own more emotional thoughts via Twitter, "I can't stop these haunting visions of her and I. We made such a lovely couple, only beginning to spend the rest of our lives together..." Before her blossoming relationship with Tequila, Johnson had a turbulent romance with the daughter of former Yahoo! CEO Terry Semel. She was extremely close with Paris and Nicky Hilton, as well as Lindsay Lohan's ex Samantha Ronson. Hilton Twittered about her grief over Johnson's passing saying, "In bed crying, looking at baby pictures of Casey, Nicky and I. I feel so upset. I feel like I've lost a sister. My heart is broken. Miss her. God has another Angel by his side. Casey, we all Love and Miss you and know that you are in a better place. R.I.P."