WOBURN, Mass. – An Irish nanny accused of killing a baby who died of what prosecutors say was “abusive head trauma” while in her care pleaded not guilty on Thursday to a murder charge.

Aisling Brady McCarthy, 34, was ordered held without bail at her arraignment on charges of murder and assault and battery on a child.

McCarthy was caring for Rehma Sabir at the baby’s family’s apartment on her first birthday, Jan. 14, while her parents were at work.

That afternoon, an ambulance was summoned to the apartment in Cambridge, just outside Boston, after Rehma was found to be unresponsive. Rehma died two days later at Boston Children’s Hospital of what an autopsy found were blunt-force head injuries, prosecutors said.

State police said in court documents that a pillow, a blanket and baby wipes that were stained with blood were found in the baby’s bedroom.

Authorities have accused McCarthy of “violently injuring” the baby, causing her death. They said a neighbor reported hearing the baby crying for nearly an hour on her birthday, followed by more intense crying, but knocks on the family’s door went unanswered.

McCarthy, of nearby Quincy, had pleaded not guilty earlier to assault and battery of a child, and she had been held on $500,000 bail. She was indicted on the murder charge last week after the medical examiner found the baby’s death was a homicide.

Defense attorney Melinda Thompson said McCarthy maintains her innocence and has cooperated with investigators.

Prosecutor Patrick Fitzgerald argued Thursday that McCarthy should be held without bail because she is in the United States illegally and if released could seek deportation to Ireland, which does not extradite defendants who could face life sentences without the possibility of parole.

Thompson has called McCarthy “an innocent person sitting in jail” and said she wouldn’t seek deportation if she were released on bail.

“She wants to answer these charges and clear her name,” Thompson said.

Immigration officials have said McCarthy entered the United States in 2002 from Ireland under a tourist program that allowed a 90-day stay.

The baby’s parents, Nada Siddiqui and Sameer Sabir, told police McCarthy had been a nanny for their family for about six months.