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FORT LAUDERDALE (CBSMiami) – The ex-wife of the man accused of killing Plantation attorney Melissa Britt Lewis, then dumping her body in a canal, has taken the stand against him.

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Lewis was a law partner of notorious convicted Ponzi schemer Scott Rothstein. She was also best friends with Debra Villegas, Rothstein’s chief operating officer.

Prosecutors say Villegas’ ex, Tony Villegas, killed Lewis in March, 2008 because he blamed her for the breakup of his marriage.

Debra Villegas testified that her ex-husband was violent man and threatened Villegas. She said she and Lewis armed themselves against his threats.

“We talked about it, neither one of us wanted a gun, she was living alone so she felt she needed something to, you know I was going through a difficult divorce and living on my own as well, so I decided on a Taser and she decided on pepper spray,” Villegas testified.

She said during their nasty divorce her husband told her something that may have foreshadowed violence.

“‘You think you’re on top now,'” she quoted him as saying.  ‘”But you and your friends will be sorry.  I’m going to win in the end.'”

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Police found pepper spray residue in the garage of Lewis home. Debra Villegas’ roommate testified that when he came home the day of Lewis’s disappearance, he found Tony Villegas washing pepper spray off of his hands and arms.

Assistant State Attorney painted a seemingly overwhelming case against Villegas in his opening statement.  He said Tony Villegas’ DNA was found on Lewis suit jacket in her abandoned SUV.  A button that had been torn of it was found on her garage floor.

Tracking records showed Lewis’ cell phone went back and forth between Broward and Miami-Dade on an FEC train line after her death.  Villegas was a conductor on the train.

The defense is expected to plant the suggestion that Rothstein was behind Lewis’ murder because, as an attorney said in an earlier civil proceedings, “she knew too much.”

Despite conspiracy theories early on, investigators say Lewis was never a part of Rothstein’s $1.6 billion Ponzi scheme and her death had nothing to do with him.

The judge has forbidden the defense from bringing Rothstein into the murder trial, but that could change if any witnesses make unsolicited reference to the Ponzi schemer.

For her role in Rothstein’s Ponzi scheme, Debra Villegas was sentenced to 10-years in prison. She won early release for cooperating with the state.

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Tony Villegas faces the death penalty if convicted of first-degree murder.