A "48 HOURS MYSTERY" Doubleheader on Sat. Jan 1

A TEENAGE GIRL IS DISCOVERED IN HER CAR, BRUTALLY MURDERED; WAS SHE RUNNING FOR HER LIFE?

CBS NEWS' "48 HOURS MYSTERY," ON SATURDAY, JAN. 1, 2011, (10:00-11:00 PM, ET/PT)

More than seventeen years have passed since Scott County, Mo., Deputy Sheriff Rick Walter pulled over on a desolate strip of highway in Benton, Mo., to examine what he thought was an abandoned car. Instead, he discovered the body of 19 year-old Angela Mischelle Lawless. Based on the blood evidence, investigators believed Mischelle, who may have been running for her life, was brutally beaten and then placed back in her car, where she was shot three times.

As Rick Walter was working the crime scene, a local man reported that he had seen the young woman in her car, and also told investigators that he saw a white car driving near the crime scene. At the same time, authorities immediately looked at Lawless' boyfriend, but could find nothing to tie him to the crime, and he passed a polygraph. Weeks went by with few leads, until four months later investigators got a break.

Seventeen-year-old Joshua Kezer had been held briefly on assault charges in the county jail where, according to several inmates, he confessed to killing Lawless. Then the man who reportedly saw a car near the crime scene identified Kezer from a photo lineup as the driver. It was all police needed. Joshua Kezer was charged with the first-degree murder of Mischelle Lawless. To many, it seemed like an open-and-shut case and Kezer was convicted and sentenced to 60 years in prison. But Walter had nagging doubts and in 2005, as sheriff, he acted on them by reopening the case.

Soon the foundation on which Kezer's conviction was built began to crumble, as witnesses admitted to lying and evidence was questioned. But would all this be enough to convince a judge to order a new trial? The outcome was stunning...and would generate new theories about what happened to Mischelle Lawless.

Erin Moriarty reports on 48 HOURS MYSTERY: "The Girl Who Knew Too Much." Click here for a sneak peek of this program.

Susan Zirinsky is the executive producer of 48 HOURS MYSTERY.