FORMER CHICAGO BEARS PLAYER SHAUN GAYLE SPEAKS EXCLUSIVELY TO "20/20" ABOUT THE MURDER OF HIS PREGNANT GIRLFIREND

Juju Chang's Report Airs On "20/20," Friday, April 15

Plus: "Black Swan" Dance Double and American Ballet Theatre Soloist Sarah Lane Talks to Elizabeth Vargas About the Controversy Surrounding the Movie

A "20/20" exclusive: former Chicago Bears star player Shaun Gayle speaks for the first time about the murder of his pregnant girlfriend and unborn child, gunned down at close range in 2007 by a woman who was secretly obsessed with him. ABC News Correspondent Juju Chang's report, which includes secret police recordings of the woman convicted of murder just last month, airs on "20/20" FRIDAY, APRIL 15 (10:00-11:00 p.m., ET) on the ABC Television Network.

Former star football player Shaun Gayle was best known for helping the Chicago Bears win the 1985 Super Bowl. That was until his seven-month pregnant girlfriend, Rhoni Reuter, was found gunned down in her kitchen. Especially horrifying was the shooter's aim, directly at Rhoni's unborn child. The headlines exploded when it was discovered that the handsome sports legend was the unborn baby's father, and when rumors circulated that he and Rhoni did not have a committed relationship, investigators put Gayle's hero status aside and became very suspicious. Then more confusion: Not only did the famous athlete provide an alibi, but he pointed the finger at someone else -- a Polish model he once dated who, he says, ended up stalking him. For almost two years the case remained a mystery, until police made a startling discovery� There was someone else who had been obsessed with Shaun Gayle -- his real estate agent, Marni Yang. But it's how the police lay a trap for this woman that has everyone surprised, resulting in a secret recording with the killer's own words detailing exactly what happened.

Video preview: http://abcnews.go.com/2020/video/pregnant-womans-murder-reveals-stalker-13366197

Slideshow: http://abcnews.go.com/Entertainment/slideshow/celebrities-stalkers-chicago-bears-shaun-gayle-3844676

Shaun Gayle's 911 Call: http://abcnews.go.com/2020/video/shaun-gayles-emotional-911-call-13356505

Plus: A real life controversy surrounding the movie "Black Swan" has unfolded: Was it Natalie Portman or Sarah Lane, the soloist ballerina with American Ballet Theatre and Natalie Portman's dance double, who did the majority of dancing in the hit movie? And was Lane asked by producers not to talk to the press about her role in the film before the Academy Awards? Lane speaks candidly to Elizabeth Vargas on this week's "20/20."

"20/20" is anchored by Elizabeth Vargas and Chris Cuomo. David Sloan is executive producer.