A HIGH SCHOOL DANCER AND ASPIRING MODEL IS FOUND DEAD - DID THE KILLER VIDEOTAPE THE MURDER? "48 HOURS" INVESTIGATES, SATURDAY, AUGUST 9

Peter Van Sant and 48 HOURS report on the murder of an aspiring model and beauty school student in an updated edition of "Secrets of the River" to be rebroadcast Saturday, August 9, 2014 (10:00 PM, ET/PT) on the CBS Television Network.

In February 2010, Mackenzie Cowell told her father they'd meet for dinner. Mackenzie never made it, and hours later police called her father, Reid Cowell, and told him they found her car abandoned some 40 miles from home. Four days later, Mackenzie was found dead alongside the Columbia River. She had been strangled, beaten and stabbed.

An unprecedented task force of FBI, state police and local authorities investigated the murder. They interviewed Mackenzie's boyfriend, who failed part of a polygraph, though had an airtight alibi. They also talked with her mother's boyfriend, with whom she had a strained relationship. And then a bombshell: an informant surfaced claiming to having seen the actual murder on videotape - shot by the killers - and she knew who they were.

Yet the biggest break came eight months later, when a tip from a prison inmate led police to a fellow beauty school classmate. That classmate, Chris Wilson, was charged with murder, and hired high-profile attorney John Henry Browne, who has represented Ted Bundy, the "Barefoot Bandit" Colton Harris Moore and Sgt. Robert Bales, who admitted to killing 16 Afghan citizens.

Wilson maintained his innocence. Would the alleged videotape of the murder clear him?

Susan Zirinsky is the senior executive producer.

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