Natasha Gregson Wagner has long made it clear she doesn't believe her stepfather, Robert Wagner, had anything to do with her mother Natalie Wood's mysterious 1981 drowning death. In a new memoir, she reiterates that view. "I know that if my mom had been in any kind of distress, he would have given his life for her," she says of Robert Wagner, who raised her and her two sisters and whom she calls her dad alongside her biological father, Wood's second husband. Wagner himself, now 90, gives People a rare interview in which he echoes that sentiment: "She said that because she knows me and she knows that I never would have done anything to hurt her mother.” More Than Love is out Tuesday, with an accompanying HBO documentary also premiering on HBO Tuesday. (People excerpts the memoir here.)