Best Bets on TV Tonight

As Easter approaches, "Secrets of the Dead" (8 p.m., PBS) looks at the long-standing controversy over whether the Shroud of Turin could really be the cloth that wrapped the body of Jesus. Though a 1988 study concluded that it was a 14th-century forgery, the question of just how old it is has not been answered to everyone's satisfaction.
"The Swan" (9 p.m., Fox): Female contestants are subjected to a rigorous three-month makeover "boot camp" in hope of becoming "the ultimate swan" of this new reality series. And they're not allowed to see themselves in a mirror during the process.
When presidential candidate Robert F. Kennedy was fatally shot leaving a political rally in 1968, the investigation by the police and FBI pointed to a single gunman, a Palestinian named Sirhan Sirhan. Five years earlier in Dallas, a single gunman also had apparently ended the life of RFK's brother, then-President John F. Kennedy. But in both cases, unanswered questions remained. "Unsolved History: RFK Assassination" (9 p.m., Discovery) looks back at the probe into RFK's death, including rumors that vital evidence had been destroyed, and questions about a conspiracy team.
The newsmagazine "48 Hours Investigates" (10 p.m., CBS) examines the case of a teenager who confessed to killing his parents. But the confession may have been forced -- and the teenager has been in prison for 15 years.