HALIFAX - The defence lawyer for a man accused of manslaughter in his baby's death accused the infant's mother on Friday of shaking their daughter and lying about what she told police the day the child was rushed to a Halifax hospital.

In his cross-examination of Jane Gomes, Donald Murray asked why she told a police constable on July 23, 2009, that seven-week-old Aurora Breakthrough had been sick since she was born.

Gomes denied making the statement during a car ride to the IWK children's hospital.

"I'm going to suggest you did say that ... because you knew you were the only one to look after Aurora pretty much for the first two weeks and for most of the first month," Murray said.

Gomes denied Murray's assertion, saying the constable must have been mistaken.

Ashiqur Rahman, 25, has pleaded not guilty in the Supreme Court of Nova Scotia to manslaughter and aggravated assault in the baby's death.

Gomes, 25, pleaded guilty earlier this year to a charge of failing to provide the necessities of life and received a conditional discharge with six months of probation. She also agreed as part of her plea to testify at Rahman's trial.

Murray accused Gomes of telling police the child had been sick because she had mistreated the baby.

"You shook her to stop her from crying ... and you hoped against hope that nobody would ever notice anything," said Murray.

Murray also questioned Gomes's motives for agreeing to testify against her former partner.

He argued Gomes grew worried about the possibility she could face serious charges when she saw a January 2010 medical examiner's report that said the baby died of "non-accidental trauma."

Police upgraded charges against the couple from aggravated assault to manslaughter in March 2010.

"You got that (medical examiner's) report in mid-February and in March the Crown summoned you to court and said 'It's not just aggravated assault anymore, it's manslaughter,' " Murray said. "And again, you didn't want to get convicted of manslaughter."

Gomes disagreed, saying she was simply taking her lawyer's advice to accept the lesser charge of failing to provide the necessities of life.

"You didn't want to run the risk of the court finding you guilty," said Murray, adding that by the end of March she had an agreement with the Crown for immunity from a potential manslaughter charge.

Murray also asked Gomes about a series of letters she wrote to Rahman's parents in Bangladesh in the months before the autopsy report where she said she still loved their son.

He noted she didn't repeat allegations she'd made to police in August 2009 that Rahman had shaken and slapped the baby that July.

Reading from a letter dated in December 2009, Murray said Gomes wrote: "It makes me feel so guilty when I think about your sufferings."

He asked if Gomes felt "guilty about things you didn't do to keep your daughter alive?"

"I'm not feeling guilty," she responded.

"It's feeling bad that I could have done this, or done that, and I would have my daughter with me."

Gomes has told the trial before a judge alone that she felt she should have left Rahman after he slapped and later shook the baby in July 2009.

Gomes became emotional and cried during the cross-examination, and at one point the judge ordered a recess.

A neuropathologist has testified that Aurora suffered extensive brain injuries prior to her death.

Aurora died on July 27, 2009, following the removal of life support, four days after her admission to hospital.