MIAMI (CBSMiami) – Adultery and the credibility of a key police investigator took center stage Thursday at the trial of Adam Kaufman, an Aventura developer accused of killing his wife Lina.

Prosecutors said Kaufman strangled his wife, Lina, in the bathroom of their home. The defense claims she had a heart attack.

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On Thursday, the defense successfully attacked the morals and honesty of Detective Ana Howell, the lead CSI investigator for the Aventura police department.

Howell had an adulterous affair with the lead homicide detective on the case, Anthony Angulo.

“I am married and have three kids. My job is very important to me,” Howell said from the witness stand, obviously uncomfortable. “This is very important to me, Sir, because this is my life here,” she told defense attorney William Matthewman.

Under withering questioning, Howell admitted to carrying on with her fellow detective .

“Did you have an affair with Detective Angulo,” Matthewman asked?

“Yes and my husband is well aware of it, Sir, and I am happily married and I don’t have any issues with that any longer,” said Howell.

On the stand, Howell admitted lying in earlier testimony; not being truthful about her relationship with the fellow cop.

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The defense called Howell a perjurer, asking if she misrepresented the facts under oath.

“Yes or no, Ma’am, is that true,” Matthewman asked.

“Yes,” she replied.

It was a damaging moment for the prosecution, a “gotcha” moment for the defense and a humiliating moment for Howel who stormed from the courtroom slamming the door behind her.

The case started in November 2007 when a hysterical Adam Kaufman called 911 and said that he had awakened after a night of sleep to find his wife in the bathroom, unconscious, her neck draped over a bar on a magazine rack.

Officer Linda Alvarez was next to take the stand.  She testified that when she arrived at Kaufman’s residence the morning of Lina Kaufman’s death, the hood of Adam Kaufman’s car was still warm.  Her testimony was intended to counter Kaufman’s claim that he had been asleep all night. On cross-examination, Alvarez said she didn’t know who had been driving the car.  In previous testimony, the state has shown that Lina Kaufman sometimes drover her husband’s Mercedes.

After Alvrez’s testimony, the judge adjoined for the day and said the trial would resume Monday 8:45 a.m.

Prosecutor Joe Mansfield maintains Lina Kaufman was a perfectly healthy woman at the time of her death and there are several inconsistencies in Kaufman’s story that he woke up and found his wife dead.

The defense claims she had a heart attack and hit her neck on a rack as she slump over.  They add that the state has offered no motive, not even a vague theory, as to why Kaufman would want to kill his wife.

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Kaufman, who is free on half million dollar, could be sentenced to life in prison if he is convicted.