Northern Virginia GOP activist Kevin Sabo took the stand in his defense yesterday, telling an Arlington Circuit Court jury that he once cared "very, very deeply" for his ex-girlfriend, Heather Lawrence, and that he never tried to harm her in any way.

"Did you cut the brakes on her car?" asked defense attorney A. Strode Brent, before Sabo had even settled into the witness chair.

"No, I did not," Sabo answered firmly.

Sabo, 38--who is accused of cutting the brake lines on Lawrence's car on March 17, causing her to crash--spent much of his time on the stand explaining statements he had made to Lawrence during phone conversations she taped. He is heard on the tapes saying that he "did something" to the car.

Deputy Commonwealth's Attorney Theo Stamos is trying to prove that Sabo, a lawyer who had served as GOP chairman in Northern Virginia's 11th Congressional District, was so upset over the breakup of an eight-month relationship with Lawrence that he attempted to maliciously wound her by cutting the brakes on her 1997 Volkswagen Jetta. A forensic scientist testified that some wire cutters found by police in Sabo's Fairfax County home were used to cut the brakes.

Lawrence, 28, who was not injured, testified that she had police install a recording device on her phone so she could try to extract an admission from Sabo, whom she began dating when they both worked at a lobbying firm in the District. He was general counsel, and still married, and she was a media relations specialist.

For more than three hours yesterday, jurors heard two of those taped conversations, including one marathon session that was punctuated with long silences and sighs. Most of the time, Lawrence is talking in a soothing voice, begging Sabo to "level with me" so she can stop living in fear.

"I've got to know," she tells Sabo again and again. "I need my life back--and I think you can give it to me. I told you--I'm not holding you responsible for anything."

Toward the end, Lawrence changes her tone, threatening to tell Sabo's wife about their affair and saying she may have no other choice than to go to police with her suspicions.

A weary Sabo finally tells her that he "did something" to her car but then says he doesn't remember precisely what. He said on the tape that he'd been drinking heavily at a bar that night. He said he then went to his Annandale home, where he "broke down and cried" because of their breakup. He retrieved some tools and drove to where her car was parked in Arlington, he said.

But he said emphatically on the recording that he has no recollection of damaging her car. "All I remember is standing at your car," he said. "What I'm telling you is that I don't know all the details. I was drunk and panicked."

When he took the stand yesterday, Sabo said he made up the story on the tapes because he feared Lawrence was about to carry out her "long-standing threat" to tell his wife about the relationship. That, he feared, would hurt his relationship with his daughter, who was then 5 years old.

"I was literally scared to death," said Sabo, who resigned his post on Virginia's Commonwealth Transportation Board in the wake of the allegations. "It was almost as though she was holding a gun to my head."

Sabo, who has been treated for depression for the last several years, testified that Lawrence had been physically violent during their relationship. He said she had punched him, ripped the prescription glasses off his face and thrown his cellular phone against a brick wall.