Video footage shows staff members at facility treating young children roughly

Prosecutors specializing in crimes against children in Shanghai's Changning district have taken up a case of child abuse that allegedly took place at the in-house day care center of Ctrip, a major online travel agency.

Video footage, which has gone viral since Monday, shows staff members at the center treating children roughly, causing some to fall. Some children were forced to swallow a substance investigators identified as mustard. Ctrip alerted police to the incident on Tuesday.