Police are appealing for a witness to come forward after a 65-year-old woman was robbed in Chorley.
It happened on Devonshire Road at about 10am on December 22.
The woman was attacked after withdrawing her pension at the post office.
She was approached by a man who assaulted her and took her hand bag before running off and was later caught by police.
The witness saw the incident, chased off the man and helped the victim back to her car and called the police, but left no details.
She is believed to have been wearing a blue jacket.
DC Andrew Doran of Skelmersdale CID said: “We are keen to speak to the woman who saw the incident as she may hold vital information about the robbery and we would also like to thank her for her actions that day.”
A 39 year old man was charged in relation to the incident and remanded in custody.