"48 HOURS" GOES INSIDE TWO INVESTIGATIONS THAT HINGE ON NEW TECHNIQUES TO SOLVE OLD CRIMES, IN A SATURDAY NIGHT DOUBLE FEATURE ON DEC. 31

9:00 PM "MOMMY DEAREST"

10:00 PM "JANET'S SECRET"

48 HOURS goes inside two investigations that hinge on new technology to help police crack decades-long cases, in a Saturday night double feature, to be broadcast Dec. 31 (9:00 PM, 10:00 PM) on the CBS Television Network.

At 9:00 PM, Richard Schlesinger and 48 HOURS look at the role socialite Linda Cooney played in the 1992 shooting death of her ex-husband, Palm Beach lawyer Jim Cooney, and the shooting of her son, Kevin, nearly two decades later with the same gun in an encore of "Mommy Dearest." In 1992, Cooney shot dead her ex-husband, while Kevin, then 10, peeked through a hole in his bedroom door. The case rocked Palm Beach when Linda went on trial for murder and was found not guilty, largely on the weight of Kevin's testimony, investigators say.

Cooney left Palm Beach with Kevin and his brother and landed in Las Vegas. Then in June 2011, 19 years after her husband was killed, she called 9-1-1 to report Kevin has been shot in the neck with the very same gun. Kevin Cooney, 30, who once saved his mother from jail, would again be at the heart of a trial against his mother.

Prosecutors maintained Linda Cooney was desperate to control her grown sons. Cooney's defense painted a different story: Kevin was mentally unstable and on the morning of the shooting, he came after his mother and accidentally shot himself. What would a jury believe?

At 10:00 PM, Peter Van Sant and 48 HOURS investigate the death of Janet Walsh and the three-decade search for her killer in "Janet's Secret." Walsh was found dead in 1979 -- it was a case that confounded investigators, though they never gave up.

Walsh was last seen by friends that she had been out dancing with in the early morning hours of Sept. 1, 1979. When she didn't show up for work, her family went to check on her at her home in Monaca, not far from Pittsburgh. She was dead in her bedroom, with her bathrobe tie used to bind her wrists. Walsh had only recently started rebuilding her life after separating from her husband.

Could a determined Assistant District Attorney and a veteran detective, armed with fresh eyes and new forensic technology, help solve a case that had five potential suspects?

48 HOURS: "Janet's Secret" is produced by Susan Mallie. Claire Anderson is the associate producer. George Baluzy, Diana Modica, Tom Costantino, Mike Baluzy and Kevin Dean are the editors. Linda Martin is the update producer. Anthony Batson is the senior broadcast producer. Susan Zirinsky is the senior executive producer.

48 HOURS: "Mommy Dearest" is produced by Patti Aronofsky and Jonathan Leach. Michelle Feuer and Cindy Cesare are the development producers. Doreen Schechter Phil Tangel and George Baluzy are the editors. Linda Martin is the update producer. Susan Zirinsky is the senior executive producer.

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