An epileptic woman was robbed while lying unconscious in the street after having a fit, West Midlands Police said.
The 25-year-old woman collapsed on her way to work in Birmingham city centre last month and suffered a seizure.
Police said a woman was seen going through the victim's bag, pretending to look for her purse. When she regained consciousness, she found that her purse was missing from her bag.
Images of two women who were at the scene in Summer Row on 22 February have been issued by officers, who are appealing for them both to come forward.
Pc David Horton, from Birmingham's Jewellery Quarter police team, said: "This was a callous and terribly sad case where a lady was taken ill just yards from her place of work, only to then become a victim of crime when completely defenceless.
"The thief pretended to be looking through the woman's bag in an attempt to find medication but the purse was then found to have gone.
"It's not clear if the two women were together or if one of the women was indeed trying to help, but we ask people to help us trace the women pictured in order to help with our inquiries."
Anyone with information is urged to contact Birmingham Central Police Station by dialling 101 or speak to Crimestoppers anonymously on 0800 555 111.