A screaming 92-year-old woman is shown being dragged along the ground during a "devastating" robbery.
Police have released footage of a hooded man following the victim as she walked down a street in Hackney, east London, on Tuesday.
The man then grabs her handbag, pulling the elderly victim to the floor and she is dragged along as the thief struggles to escape with her belongings.
Detectives said the woman was in so much pain she eventually let go of her bag.
Detective Inspector Paul Ridley from Hackney CID, who is leading the investigation, said: "I have been involved in many serious cases, however the devastating psychological trauma of this victim is possibly the worse I have encountered.
"I cannot comprehend how anyone could target a frail lady in her 90s using this amount of violence, it is truly horrific.
"We have clear CCTV of the attacker. All I need is a name. There are a team of officers on standby ready to arrest him."
Officers said the handbag contained a £50 mobile phone, £100 cash and a travel pass.
The woman was heading to the Lawson Medical Centre in Nuttall Street after posting a letter when the thief struck at around 2.40pm.
The suspect, described as a black man with short black hair and wearing a blue hoodie, ran into the alleyway by the medical centre and turned right, heading north, in Hoxton Street.
Anyone with information is asked to call police on 101 or Crimestoppers anonymously on 0800 555111.