Detectives want to speak to a woman who may have seen two bank robbers.
They may have passed her in an alleyway just off George Street in Hove at the time of the robbery last Thursday.
Sussex Police said: “Two men threatened staff delivering cash to the Santander Bank in George Street at around 11.30pm on Thursday 23 September.
“They handed over the cash and the suspects ran off up George Street in a northerly direction before running down an alleyway to the side of the Cliftonville Pub.
“The woman is seen to lean a bike against the wall opposite the bank before walking south along George Street.
“She then acknowledges someone in the alleyway where the robbers came from and then made their escape.
“Police are asking her to come forward as she may hold vital information.”
The alley runs from George Street to Haddington Close, by St Andrew’s churchyard and the Tesco car park.
The woman – and anyone else with information – is asked to contact Sussex Police on 0845 6070999 or call the independent charity Crimestoppers anonymously on 0800 555111.