Police are appealing for witnesses after a woman was raped in north London when she stopped to help a man in the street.
The woman was walking in Wontner Close, Islington, when a man asked her for some change.
She gave him the money she had, but the man grabbed her by the shoulder and pushed her into Heddington Close where he threatened the woman, who is in her late 50s, with a knife and raped her.
The attacker then took valuables from the woman's handbag and walked off towards Popham Road, police said.
No arrests have been made and police are appealing for information.
The suspect is described as a "dark-skinned black man, between 5ft 4in to 5ft 6ins of medium build wearing dark clothing, either black or dark blue". He is believed to be aged between 30 and 40.
Detective Constable Sarah Hunter from the Met's Sexual Offences, Exploitation and Child Abuse Command said: "This was a horrific attack on a woman who had stopped to help a stranger when he asked her for some change.
"Were you in the area at the time of attack? Did you see anything suspicious? My team are keen to hear from anyone who has information that can assist the investigation. This was a callous attack which has left the victim very traumatised."
Anyone with information should contact the Sexual Offences, Exploitation and Child Abuse Command on 0208 733 5999 or call Crimestoppers anonymously on 0800 555 111.