Jane Snead relived for a Fairfax County jury yesterday a phone conversation she had on July 28 with her daughter's baby sitter, Martha E. Guba. She was called at work and told her child was dying.

"Ashley's dying! Ashley's dying!" Snead said Guba shouted into the phone. "I said, 'Martha, call 911!' She said, 'They're here; they're here.' " Snead testified that when she hung up the phone, "I felt like my legs fell off my body."

With the exception of two jurors who reached for tissues, no one moved in the fifth-floor courtroom at Fairfax Circuit Court yesterday as Snead delivered her testimony on the second day of the baby sitter's trial. Guba, 58, is being prosecuted on a felony charge of neglect in the death of Ashley Snead, one of several children she provided day care for in her Springfield home.

Initially, the 10-month-old girl was thought by a medical examiner to have been a victim of sudden infant death syndrome. But a toxicologist studying Ashley's tissue and blood samples found the cause of death to be an overdose of a prescription drug. Guba was later indicted, and if convicted on the neglect charge could be fined and receive a maximum sentence of 10 years in prison.

Defense attorney Thomas J. Morris Sr. has not yet presented his case to the jury. In his opening statement, Morris described Guba, who is on a county-supplied list of day care providers, as a "loving, concerned baby sitter."

Assistant Commonwealth's Attorney Raymond Brownelle has been building his case before the jury on the theory that Guba, in an effort to silence Ashley's cries, administered the drug, imipramine, which is used to treat depression in adults and bed-wetting in children older than age 6.

During cross-examination yesterday, Morris asked Snead, who works at Dominion Federal Savings and Loan Association's headquarters at Tysons Corner, whether she had ever doubted Guba's competence in the eight months she had left Ashley in her care.

"Sir, with all due respect," Snead, 38, replied. "I look back now and remember things . . . . Why didn't I do so and so? What if I had done so and so?"

Snead testified that Guba had expressed great interest in her child, remembering how the baby sitter would cuddle her daughter and say, "Oh, I love you, little Ashley." But Snead questioned, "How did my baby get those drugs?"

An Annandale doctor testified on Tuesday that he had prescribed imipramine to Guba repeatedly in the last two years for her own depression. Yesterday, a neighbor, Kate Simcox, testified Guba had given her the drug to help combat a sleeping problem.

Simcox also said she had questioned Guba about a brown liquid she saw in some of Ashley's milk bottles. Simcox said Guba told her Ashley suffered from Down's Syndrome, adding, "You don't ask Jane questions about this."

Snead testifed that Ashley, her only child, did not have Down's Syndrome, but was a happy, healthy baby.