Rhoni Reuter was killed at her home in north suburban Deerfield in October of 2007.
Police arrested Marni Kay Yang, 41, on Tuesday morning at her Chicago home in the 5000-block of North St. Louis.
Police say the woman charged with killing Shaun Gayle's girlfriend and her unborn child is also his realtor and may have used personal information she was privy to pursue and eventually murder the woman he loved.
Marni Yang is a real estate agent, a mortgage broker, a mother and now an accused killer.
"She's the person who has a chip on her shoulder and something was amiss," said Maria, murder suspect's neighbor.
"They were fine with me. We moved in about the same time, about 15 years ago, 1995. Other than that, nothing out of the ordinary," said Kevin Hargrove, neighbor.
Yang is charged with firing the fatal shots that killed Rhoni Reuter insider her Deerfield townhome in the fall of 2007. She was seven months pregnant.
The father of her unborn daughter is a member of the 1985 Bears Super Bowl team, Shaun Gayle.
Mr. Gayle's history with the murder suspect goes back several years.
Gayle's attorney describes the two as friends who did not at the time of the murders "have a dating relationship."
Ms. Yang and Mr. Gayle owned some property together, and she represented him in several real estate deals.
Gayle released a statement on Tuesday night saying, "I am completely shaken that someone I knew is responsible for this monstrous act…this was the act of a heartless psychopath."
"Her reaction was obviously surprised. She is not talking. She asked to speak to her attorney and we're giving her that right," said Deputy Chief Rick Wilk, Deerfield Police.
"It's really a relief. I'm glad to hear that it's finally behind us and we can move on," said Phyllis Lerman, victim's neighbor.
Police say Yang has been a suspect and under surveillance for much of the last year. On Tuesday night, she is behind bars in Deerfield. On Wednesday, she will be in bond court and that's when we may hear prosecutors' motives for the murder.