While many of the people who worked with Michael Jackson on his "This Is Is" concerts expressed surprise at his struggles with drug addiction, sister Janet Jackson told ABC News that she and her family were well aware of her brother's demons.

In fact, Jackson said that she and her family reached out several times over the years to confront Michael about his drug problem and stage interventions, to no avail. "That's what you do," she told interviewer Robin Roberts in a sit-down in which she also blamed Jackson's personal physician, Dr. Conrad Murray, for the singer's death. "Those are the things that you do when you love someone. You can't just let them continue on that way. And we did a few times. We weren't very successful."

The youngest Jackson sibling said Michael, to whom she was very close, understood that his family was trying to help him, but that he was "possibly" in denial about the extent of his problems. "I wish he could answer this question for you and not me," she said. "I felt that he was in denial."

A coroner's report found that Jackson died of a lethal amount of the powerful surgical anesthetic propofol, a drug he reportedly used to combat his chronic insomnia and which Murray has told police he administered to Jackson several times on the morning of the singer's death. Jackson told Roberts she thought Murray was responsible for her brother's death.

"You can't make 'em drink the water," Janet tells Roberts about forcing someone to face their addictions. "It's something that you can't do for them, something they have to do for themselves." Janet also revealed in the interview that she learned first-hand what the ravages of addiction can do during her first marriage to James DeBarge, who has admitted a prescription medication dependency. After eloping with the singer, Jackson said their marriage fell apart after three months due to DeBarge's addiction.