An Arlington judge yesterday rejected a prominent GOP activist's attempt to suppress statements he made to his ex-girlfriend about tampering with her car.

Kevin M. Sabo, 38, a former congressional candidate and a member of the Virginia transportation board, is accused of cutting the brake lines in his ex-girlfriend's car, causing her to crash.

He is to stand trial next week on a charge of attempted malicious wounding.

An attorney for Sabo has said the woman, Heather Lawrence, "lied and threatened" Sabo to cajole a false admission out of him. Using equipment provided by police, Lawrence, 28, taped hours of phone conversations with Sabo, including one in which he told her that he had gotten drunk, obtained some wire cutters and done something to her car.

But Circuit Judge Joanne F. Alper, after listening to the tapes in her chamber, denied the defense motion to suppress the tapes as evidence at Sabo's trial. Alper said that although police provided the tape recorder and tapes, Lawrence was not acting as an "agent of the state" when she made the recordings, but instead was trying to find out for her own peace of mind whether Sabo or someone else was trying to hurt her.

Even if Lawrence had been working for police, there was little evidence on the tapes of threats being made by Lawrence to coerce an admission, Alper said.

"He chose voluntarily to stay on the phone," Alper said. "He could have hung up the phone. He was not a man being coerced improperly."

Alper's ruling also allows the prosecution to use evidence seized from Sabo's Annandale home--a tool that police said was used to cut her brakes. Sabo's attorney had argued that the evidence should be suppressed because the phone statements were used to obtain the search warrant.

Deputy Commonwealth's Attorney Theo Stamos argued at a hearing Wednesday that Sabo cut the brake lines on Lawrence's 1997 Volkswagen Jetta because he was upset over their breakup the day before.

Lawrence, a media relations specialist, testified that she met Sabo in April 1998 when they both worked for a lobbying firm in the District and that they became involved that summer, before Sabo was separated from his wife.

She said she was on the way to work March 17 when she drove out of her parking lot in Arlington onto Brookside Drive and realized to her horror that she had no brakes. As she approached the busy intersection with Washington Boulevard, she swerved across a median and crashed into a fence, she said.

Sabo's attorney, A. Strode Brent Jr., argued that his client's "involuntary admissions" were made by a man who was being treated for depression and was therefore susceptible to saying things he didn't mean. Sabo testified that he was most shaken by Lawrence's threat to tell his ex-wife about their affair, because he feared it would damage his relationship with his daughter.