Child Abuse Squad detectives have charged an 18-year-old man with the aggravated indecent assault of a four-year-old girl at a library in Cessnock, in the state’s Hunter region.

Police were told the girl was in the library’s play area on Wednesday 6 May 2015 when she was approached by an 18-year-old man.

The man allegedly kissed and touched the child before he was challenged by a witness. The man was not known to the child.

Detectives from the Child Abuse Squad at Newcastle commenced investigations and arrested an 18-year-old man at Cessnock Police Station on Friday afternoon.

He was charged with aggravated indecent assault and granted conditional bail to appear at Cessnock Local Court on Wednesday 20 May 2015.

The Child Abuse Squad is comprised of detectives who are specially trained to investigate crimes against children, including sexual assault, physical abuse and serious cases of neglect. The squad works with the Department of Family and Community Services and NSW Health.