As the prosecution presented the case, Jean Harris, as her lover lay dying, was unfeeling. She sat on his bed, not offering to help. She fled the house after the shooting and when she returned she did not show remorse.

"He slept with every woman he could, and I'd had it," she told the police. When they attempted to speak to her of homicide, her thoughts were somewhere else. "Who did he have for dinner?" she snapped.

Today, as the defense in the Harris murder trial began presentation of its case, the image changed. Harris, her former lawyer testified, was much aggrieved after being charged with the shooting of Dr. Herman Tarnower. Found by the lawyer, William Riegelman, in the Harrison, N.Y., police station on the night Tarnower was shot, Harris, according to Riegelman, "was quietly crying." There was a "bad" bruise on her lip (prosecution witnesses have termed it minor) and bloodstains on her blouse. And when she was told her wounded lover had just died, she was visibly upset.

"She sobbed. She said, 'Oh, no!', something of that kind, she was terribly grief-stricken," Riegelman said.

"Objection. Conclusory statement," interrupted the prosecution.

"She sobbed very, very heavily," began the witness again. "She leaned on my shoulder and sobbed."

The former headmistress of the Madeira School in McLean, Va., Harris has been charged with second-degree murder in the shooting death of Tarnower in the bedroom of his home in March. The prosecution, which has argued its case for over a month, maintains Harris shot her lover of 14 years, who had been seeing a younger woman, in a jealous rage. The defense has maintained the shooting was "a tragic accident," a suicide attempt gone wrong.

Today, the defense, led by attorney Joe Aurnou, began to detail its side of the story, and the outlines of the tale, as well as the mood of the defendant, seemed considerably changed.

Harris, who was dressed Monday in melancholy gray, her hair held firmly in control by her trademark headband, feet nervously tapping, was today dressed in colors of almost spring-like hue -- beige skirt, a pale lime blouse. The headband was gone. Gone also was the yellow notepad on which she has busily scribbled notes. Harris did, upon hearing testimony of her night in jail, dab at her eyes with a bit of pink tissue, twist her hands nervously and stare straight ahead.

But for the most part, her mood and manner seemed almost cheery. She chatted with Riegelman, an attorney with the prominent Wall Street firm of Fried, Frank, Harris, Schrieber and Jacobsen, when he was away from the stand. She had a hug for her daughter-in-law. She laughed, with the others, at the occasional courtroom joke.

The testimony, as the defense began its case, was mixed, drawn from a half dozen witnesses. Central was Riegelman's dramatic account of Harris' breakdown the moment she learned Tarnower was dead. But equally important -- and much more tantalizing -- were references made throughout the day to several letters and documents which had been retrieved from Harris' Virginia home the day after Tarnower was shot.

In his opening statements, Aurnou had referred often to those statements, saying Harris had never meant to return to Virginia alive, suggesting that the notes, written to relatives and close friends, were in fact suicide notes.

Today, Aurnou -- without divulging the contents of those notes -- made a great point of them. He introduced several witnesses, including messengers who had delivered the letters from Virginia and picked them up in New York, to identify them. He bandied the letters about, asking witnesses if the handwriting and Madeira School letterhead on the stationery were familiar to them.

Testimony never confirmed the identity of the people to whom the letters had been addressed, although one witness, an attorney from the Washington office of Fried, testified that she recalled one letter being addressed to an Alice Faulkner, and one to David Harris, Harris' eldest son.

An additional defense witness was one of Harris' former employers, John Chandler Jr., headmaster of the Grosse Pointe University School during a 14-year period beginning in 1949. The white-haired Chandler, attired in a dapper striped shirt and bow tie, said under questioning by Aurnou that Harris "was one of the most highly respected members of the school, as well as Grosse Pointe."

In response to further questioning, Chandler said he had never heard "an adverse word against her [Harris'] reputation." Aurnou asked if he had even heard "an adverse comment" regarding her reputation for "peaceability." Never, Chandler replied.

Under cross-examination, however, the character witness did not do well. Chandler was forced to admit he had not seen much of Harris in the past 15 or so years and had never visited her at Madeira. ("I haven't been on the Madeira campus for 10 years," he said.) Nor did he do well on the subject of peaceability.

"When was the first time you had occasion to discuss Mrs. Harris' reputation for peaceability?" asked prosecutor George Bolen. Then, after an objection from the defense: "When was the last time before March 10 [that] Mrs. Harris' reputation for peaceability came up?"

"I never had any point to discuss Mrs. Harris in terms of peaceability," Chandler said.