A little girl, who may be as young as four, was allegedly assaulted by a drunk man close to a Tesco supermarket.
A local hero, unrelated to the girl, came to her aid when she was attacked at 7.15pm on Saturday night, according to police.
Officers have appealed for the hero to come forward in order to help them with their investigation into the incident.
West Mercia Police were called to the retailer in Hereford following reports of a public order disturbance.
A man, who remains in police custody, was arrested for being drunk and disorderly as well as for assault.
Anyone with information is asked to please contact PC Thomas Henry on 07773 052979 or by email Thomas.firstname.lastname@example.org.
People can also contact the independent charity Crimestoppers anonymously by calling 0800 555 111.