The robbery happened in the Doncaster Road area of Scunthorpe at 4.20pm on Saturday, December. 10.
The victim's handbag, containing cash, was stolen and she was knocked to the ground.
She was not hurt in the incident.
And today (Wednesday) police have released CCTV images of a man they want to speak to in connection with the robbery.
Anyone with information should call Humberside Police on 101 quoting crime reference number BI/2235000.
Calls can also be made anonymously to Crimestoppers on 0800 555 111.