SATURDAY, APRIL 19, 2014, 10:00 PM, ET/PT

Caption (L-R): Amy and Emily Weidner; Emily Weidner.

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Can a family find out who murdered a young mother more than two decades earlier with the help of a Facebook-savvy police officer who never worked a homicide case?  Troy Roberts and 48 HOURS report on the family’s quest for answers to the murder of Amy Weidner and a dedicated officer’s search for her killer in “Decades of Deceit” to be broadcast April 19, 2014 (10:00 PM, ET/PT) on the CBS Television Network.

Weidner was beaten, sexually assaulted and killed in the bedroom of her Indianapolis home whileshe and her 2-year-old daughter were home alone on Nov. 13, 1989. She was found by her mother, Gloria Weidner, who returned to the houseafter her daughter couldn’t be reached by phone.

“She was terrified. That’s how she died. Terrified,” Gloria Weidner says.

Weidner says she didn’t know what happened to her daughter. “The word ‘murder’ is just a really hard word,” she tells 48 HOURS. “But, the truth is she didn’t just die. Another human being did this.”

Amy Weidner’s daughter, too young to know exactly what happened in that bedroom in 1989, wonders what her mother would be like today. “Would she have gone to college?” Emily Weidner says. “What would she have done with her life? I imagine that Amy and I would probably be friends, not just mom and daughter, but friends.”

At the time of the murder, Gloria Weidner was sure police would see they were a good family and find the killer.

There was a bloody handprint on the bedroom wall. Police believed she was killed by an acquaintance and chased down many leads, none of which led to an arrest.

And then the case went cold.

The Weidner’s case eventually landed in the Indianapolis Metropolitan Police Department’s cold case unit. In 2011, in response to a newspaper article about the case, friends created a “Remembering Amy Weidner” Facebook page. The detectives in the cold case unit were not well-versed in using Facebook, but knew a colleague who was, Detective Sgt. William Carter, a nuisance abatement officer.

They asked Carter for help printing some pictures from the Facebook page. In the process, he became obsessed with solving the crime – and helping the family.

“I spoke to Gloria Weidner,” Carter says. “She had lost all hope, and it kind of just made it a personal thing for me.”

He jumped on the case using his own time and soon found a lead others had missed. The stunning revelation would send the investigation on a path no one expected.

“You have 24 years of always wondering why this happened,” says Emily Weidner. “Why did they not find anyone, is he still out there?”

Using advanced technology, forensic evidence was reexamined and a new link uncovered. But would it provide the family with some long overdue answers?

“We expected to hear a name that we did not know,” says Gloria Weidner, “not someone that we knew.”

Roberts and the 48 HOURS team tell the story through interviews with the Weidner family, Carter, and Captain Jack Geilker of the Marion County Sheriff’s Office, who in 1989 was one of the first on the scene of the crime as a member of the Indianapolis Police Department, as well as other family friends.

48 HOURS: “Decades of Deceit” is produced by Ruth Chenetz. Dena Goldstein is the associate producer. Anthony Batson is the senior broadcast producer. Susan Zirinsky is the senior executive producer.

Chat with members of the 48 HOURS team, as well as Detective Sgt. William Carter, during the broadcast on Twitter and Facebook. Follow 48 HOURS on Instagram.

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Press Contact:  Richard Huff      212-975-3328    huffr@cbsnews.com