An Irish nanny accused of slamming an infant against a wall and changing table before presenting its lifeless body as sleeping to its relatives has pleaded not guilty to murder. Defense attorneys for Aisling Brady McCarthy, 34, say the baby was already 'sick' and 'not normal' while in her care before found bruised and unconscious in her family’s Cambridge, Massachusetts home last January. Prosecutors say Rehma Sabir was hospitalized with severe head injuries on her first birthday, January 14, before being declared brain dead two days later. Plea: Irish nanny Aisling McCarthy Brady, 34, has pleaded not guilty to murdering an infant in her care last January No bail: McCarthy, who has been in the United States illegally for the last 13 years, is being held without bail on charges of first-degree murder and assault On Thursday Prosecutor Patrick Fitzgerald said McCarthy violently shook Rehma, possibly bouncing the infant's skull off a changing table and a wa