THUNDER BAY, Ont. -- Police say a 23-year-old Thunder Bay, Ont., woman is facing a number of charges related to alleged child pornography involving a girl she knows.

City police say they began investigating the woman last month after learning that she was allegedly uploading pornographic images to the social media site Tumblr.

They say the alleged victim in the case was a girl under the age of 10 who was known to the woman, though they did not disclose the nature of their relationship.

Police say the woman is facing five charges, including one count each of making child pornography, sexual assault and sexual interference.

Thunder Bay police say the fact that the accused is a woman, coupled with the severity of the case, prompted officials with the National Child Exploitation Co-ordination Centre to interview the woman.

Police say the woman has been held in custody after appearing in court on Friday morning.