Police have released an e-fit after a robbery outside the Tesco store in Tring Road, Aylesbury.
The victim, a 69-year-old woman, was leaving the store between about 10am and 10.30am on Monday September 21.
As she was leaving she bumped into a man, who stole her debit card from her coat pocket.
The offender is white, in his late teens or early twenties, about 5ft 11ins to 6ft and was wearing a hat.
He was with a woman who is about 5ft 6ins, was wearing dark clothing and had her head covered.
Investigating officer Det Con Paula Benson said: “I would appeal to anyone who recognises the man in the E-fit to come forward by visiting your nearest police station or by calling 101.
“I would also appeal to anyone with any other information about the incident, in particular if you saw a man and a woman acting suspiciously in the vicinity of Tesco in Tring Road at about 10am on Monday 21 September.”
Anyone with information should either call police on 101 or Crimestoppers anonymously on 0800 555 111.