A nanny who was caught on videotape beating a 9-month-old baby girl and stuffing a towel into her mouth was sentenced Friday to four years in a New Jersey state prison.

Morris County Superior Court Judge Lewis Weinstein gave Irish immigrant Siobhan Diaz, 30, the maximum sentence requested by prosecutors for endangering the child, who suffered no permanent injuries and will be 3 in August.The case was the first in New Jersey to test the constitutionality of using videotapes of nannies as court evidence. Superior Court Judge Catherine Langlois upheld that right during Diaz's trial last year, denying a challenge by her attorney to suppress the evidence.