The defense in the Jean Harris murder trial wanted to exclude this testimony. They'd had over a month of pretrial hearings, exhaustive in detail, to try to establish that the statement Harris had given a police detective the night her lover was shot should be found inadmissible. It had been obtained improperly, the defense argued. It had been obtained before Harris had properly been informed of her rights.

But the defense lost.

So today, in the ninth day of the Harris trial, the jury heard testimony from what may be the prosecution's most powerful police witness: detective Arthur Siciliano. It was Siciliano -- a cop's cop who wears his gun in an ankle holster and sits ramrod straight on the witness stand -- who, while cruising in his car, heard the radio call "Burglary in progress. Women screaming for help. Shots fired. A man down."

It was Siciliano who sped toward Dr. Herman Tarnower's house in the heavy March rain, running up the stairs of the diet doctor's $500,000 home. And it was Siciliano, met at the doorway by Harris and Suzanne Van der Vreken, housekeeper to Tarnower, who heard Jean Harris' dramatic admission.

"I said, 'What happened?'" Siciliano testified, under questioning from assistant district attorney George Bolen. "She says, "The doctor's been shot." I said, 'Where is he?' She said, 'Upstairs.' I said 'Who did it?' She said, 'I did.'"

The former headmistress of the Madeira School in McClean, Va., Harris, 57, has been charged with second-degree murder in the shooting of Tarnower, the man who created the best-selling Scarsdale diet. The prosecution, noting that the 69-year-old cardiologist had been seeing his 37-year-old assistant, Lynne Tryforos, as well as Harris, has spoken of a love triangle. aThe prosecution charges that Harris shot the doctor, her lover of 14 years, in a jealous rage. The defense maintains that the shooting, last March, was a "tragic accident," a suicide attempt gone awry.

But things, of late, have not gone well for the defense.

Harris has suffered the testimony of Tarnower's housekeeper, who claims that Harris was aware of the relationship between the doctor and Tryforos and vowed to "make their life miserable." The defense also faces, next week, the continuing testimony of Siciliano -- strong testimony, as it came out in last month's pretrial hearings.

And today, defense attorneys suffered another defeat. A long, rambling letter Harris wrote to the doctor the day he was shot -- and which was later retrieved by the defense team -- was ordered turned over to the judge, although defense attorney Joel Aurnou had argued long and hard to keep it out.

Relinquishing the letter, Aurnou had argued in the Second Appellate Division in Brooklyn, would violate attorney-client privilege. It would also violate his client's constitutional rights against self-incrimination.

The prosecution, however, had argued that because Aurnou had indicated that he might refer to the letter during the trial, the prosecution should be able to see it as well. The Appellate Division ruled for the prosecution, 3 to 2.

Here in the Westchester County courthouse today the testimony -- drawn by the prosecution from three police officers -- did not go well for the defense, either.

Particularly poignant this morning was defense attorney Aurnou's attempt to recreate the drama of the moment -- after Harris' arrest for assult -- when she learned of Tarnower's death.

That moment came when Harris was in conference with her then-attorney, a Mr. Jacobson, at the Harrison, N.Y., police station. Alas, the stolid police desk sergeant, John Carney, who had told Harris of the doctor's death, could prompt no sympathy in the courtroom for the defendant, despite the machinations of the dramatic Aurnou.

"You told her that the doctor was dead"? thundered Aurnou. "What you do -- just say, 'He's dead.'? What exactly did you say?"

Unimpressed, the cop told him.

"I said, 'At this time, the charges under which you were previously being held are being dropped and the charge of murder in the second degree is being lodged in the result of Dr. Tarnower's passing on.'"

"Do you remember what she did then?" said Aurnou, still impassioned.

"She turned toward her attorney . . . I think . . . as I remember it, he put his arm around her . . ."

"You don't recall anthing else?" said Aurnou, still hoping.

"I think if anything substantial happened I would have remembered it," said the officer.

The trial continues Monday.