WAS MURDER THE PAYBACK FOR A MAN WHO LIVED LIFE ON THE EDGE? "48 HOURS MYSTERY" SATURDAY, OCT. 22

A successful real estate agent, David Nixon of Grapevine, Texas, lived what friends say was a life on the edge. According to his live-in girlfriend, Tracy Frame, he spent money extravagantly, gambled, hired prostitutes and owed the IRS and others large sums of money. In April 2002, his brutally murdered body was discovered in a storm drain in a nearby town. He had been shot in the heart and his remains burned beyond recognition. So, who wanted Nixon dead? Correspondent Troy Roberts reports for 48 HOURS MYSTERY: "Secrets and Lies of Grapevine Lake," to be broadcast Saturday, Oct. 22 (10:00-11:00PM, ET/PT) on the CBS Television Network.

Police investigating the murder focused almost immediately on Frame, Nixon's girlfriend after two failed marriages. Nixon and Frame had a stormy relationship and their frequent arguments over money were well known in the small Grapevine Lake community. At the time of Nixon's murder, the couple was in the process of splitting up for good and fighting over the house where they both lived.

In her talks with investigators, Frame claimed that she knew nothing about Nixon's disappearance and denied any wrongdoing. She also claimed that any number of people could have wanted Nixon dead. The night he disappeared, Nixon was supposed to meet Jerry Vowell, a used car dealer who Frame says was in the business of loaning money to people.

Donna Lella, Nixon's first wife and mother to their son, claims that Nixon told her to tell police that if he was murdered they should look at Frame. Frame says Lella stood to gain the most by Nixon's death because their son was the beneficiary of his father's $500,000 life insurance policy.

Three years after Nixon's death, Frame would stand trial for murder. The prosecutor, Assistant D.A. Sean Colston, bases his case on surveillance videotape of Frame buying cleaning supplies at a local grocery store, supplies that, he claims, were used to get rid of Nixon's blood stains. Perhaps even more incriminating, the person who bought those supplies used a discount card registered to Frame, though Frame insists she's innocent and says the person on the store video looks nothing like her. What's more, Frame and her lawyer say there is no physical evidence to prove who killed Nixon: no gun, bullets or blood. Will Frame convince the jury that she's innocent of murder?

48 HOURS MYSTERY: "Secrets and Lies of Grapevine Lake" is produced by Peter Henderson. Anthony Batson is the senior producer and Susan Zirinsky is the executive producer.