A BEACH MURDER MYSTERY -- DID A HUSBAND KILL HIS WIFE AND SHOOT HIMSELF IN THE PROCESS IN THE HOPE OF BEING SEEN AS A VICTIM AND NOT A SUSPECT? -- DEBORAH ROBERTS REPORTS ON �20/20,� FRIDAY, JULY 7 ON ABC

* Also: A Brian Ross Exclusive -- A Medical Ethics Question: Using Unsuspecting Trauma Victims as Guinea Pigs; * JuJu Chang Reports on Conquering Bad Habits; * Lynn Sherr on the Height of Vanity� High on Heels

Expecting a romantic rendezvous, April Barber, 26, walked with her husband, Justin, to the water on the beach in Ponta Verda, Florida. What happened next remains a mystery. What is certain is that she suffered a gun shot to her left cheek and Justin endured four gun shot wounds. She died; he survived. Investigators were immediately suspicious of Justin�s story � he says an armed man had shot both of them in a robbery-gone-wrong type scenario. Further investigation revealed that Justin had five affairs during their brief three-year marriage. They also discovered he was the sole beneficiary of a two million dollar insurance policy taken out on April�s life. But no murder weapon was ever found. Two years after April's death, Justin Barber was arrested and charged with first-degree murder. He maintains his innocence. Was it a case of being at the wrong place at the wrong time, or did a calculating husband stage a horrific murder with the hope of cashing in the insurance policy?

For the first time Justin, an accomplished business analyst, top athlete and valedictorian of his high school class, talks to ABC News Correspondent Deborah Roberts about losing his wife, being accused, the jury�s verdict and his defense. �20/20� airs on FRIDAY, JULY 7 (10:00-11:00 p.m., ET) on the ABC Television Network.

And: Is it possible that you might have been used as a medical guinea pig without your knowledge? ABC News Chief Investigative Correspondent Brian Ross reports on a medical experiment on unsuspecting accident patients brought into hospital ERs that has been happening in more than 20 cities across the country. What is being tested is an experimental, artificial blood substitute known as Polyheme, developed by a company called Northfield labs. The sponsors of the study say using accident victims for the experiment without their consent is necessary for the greater good to safe lives of severely injured patients in the future. But critics call the test an unconscionable breach of medical ethics and a violation of the fundamental notion of informed consent.

Plus: Being messy, being a shopaholic, being late for everything, nail-biting, compulsively checking your e-mail, gossiping or hair twirling are all -- according to educator, life coach and author Judith Wright -- bad habits that are soft addictions. As JuJu Chang reports, often these bad habits stem from deep rooted problems. �20/20,� with the help of Wright, brings together several people willing to go public in the hope of conquering their own bad habits, while helping other viewers do the same.

Also: Lynn Sherr reports on the great lengths some women will go to be at the height of fashion and fit into fancy footwear, including having their feet surgically altered.

�20/20� is anchored by Elizabeth Vargas and John Stossel. David Sloan is executive producer.