UNION, S.C. -- Visibility was only about a foot when Steve Morrow, a diver searching for a missing car, floated to the Burgundy Mazda that lay upside down in the cold water of John D. Long Lake last autumn.
"I had to put my light against the window, and peered in," Mr. Morrow testified yesterday in the murder trial of Susan Smith. "I was able to see a small hand pressed against the glass."
Inside the car with the bodies of Mrs. Smith's sons -- Michael, 3 years old, and Alex, 14 months -- was a letter from the man she loved telling her that their relationship would never work, in part because of her children.
As the diver's testimony took the jury under the lake and inside the car, people in the courtroom gasped, some bowed their heads, and Mrs. Smith, charged with murder for drowning her sons by allowing her car to roll down a boat ramp and into the lake, chewed her nails and sobbed without making a sound.
But the account by Mr. Morrow, a diving expert with the South Carolina Department of Natural Resources who found the car more than a week after the drownings, was only a part of a gripping day of testimony.
Earlier in the day, the jury heard Mrs. Smith's former lover, the son of a wealthy mill owner, confirm that he had written the letter telling Mrs. Smith that he did not want a relationship that included children.
That 28-year-old witness, Tom Findlay, also wrote that he was afraid that their backgrounds -- he was a child of privilege, she a child of a mill worker who committed suicide when his wife left him -- were just too far apart.
"Like I told you before, there are some things about you that aren't suited for me, and yes, I mean your children," said the letter, written on Oct. 17, just eight days before Mrs. Smith drowned her children.
"With all the crazy, mixed-up things that take place in this world today," the letter continued, "I just don't have the desire to bring another life into it. And I don't want to be responsible for anyone else's children, either."
The prosecution introduced the letter and Mr. Findlay's testimony to portray Mrs. Smith as selfish and malicious, a woman prepared to trade the lives of her children for a chance to reclaim him.
But the defense may have also profited from his testimony. Mr. Findlay, who smiled briefly at Mrs. Smith when he took the stand, characterized her as a sweet, loving person, not the monster that the prosecution hopes to portray.
Even one of the more curious moments of their relationship -- her telling him on the day of the drownings that she had once slept with his father -- did not seem to have left him with any ill will toward her.
(Mrs. Smith later told him that she had fabricated that story, an apparent effort to return some of the pain that he had instilled in her, "as a joke," Mr. Findlay testified.)
On cross-examination, Mrs. Smith's lawyer, David Bruck, asked Mr. Findlay whether he had ever had reason to believe that Mrs. Smith would harm her children to win him back. Mr. Findlay said no. "They were her world," he said.
The defense also profited from an unexpected disclosure during Mr. Findlay's testimony. That disclosure concerned Mrs. Smith's estranged husband, David Smith, who, because of his grief over the loss of his sons, is expected to be one of the state's most compelling witnesses.
Mr. Findlay testified that when he called Mrs. Smith's house on one occasion, Mr. Smith snatched the phone from her. On that occasion, Mr. Findlay said, Mr. Smith threatened to hurt him if he ever called again.