Nearly four decades after the unexplained drowning death of Hollywood star Natalie Wood, Los Angeles County Sheriff's investigators tell "48 Hours" that her then-husband, actor Robert Wagner, is now a person of interest. Investigators want to speak with Wagner about the circumstances surrounding her death one night in 1981, they say in interviews for "Natalie Wood: Death in Dark Water" to be broadcast Saturday, Feb. 3 at 10 p.m. ET/PT on CBS.