A robber armed with a suspected homemade bomb has targeted five bookmakers, police have said.
The suspect produced the 'bomb' and demanded cash
The device is described as a wired-up wine bottle covered in a white powder similar to flour, with a three-pin plug on the end of it.
In one case, the man threatened staff with the object and ordered them to fill up his bag with cash at Ladbrokes in Croydon, south London, on 8 May.
He is described as black, slimly built, 5ft 4ins to 5ft 8ins, aged in his 30s.
'Fill it up'
Scotland Yard have released CCTV images of the robbery at the Ladbrokes in Surrey Street, Croydon.
He entered the store at about 1000 BST and waited by a counter appearing to look at the racing sheets on the wall, said police.
After about five minutes, he approached the counter where two members of staff were working and said: "Fill it up".
He then opened up a white plastic bag containing an object that looked like a homemade bomb and showed it to cashiers.
Staff placed a bundle of cash into the bag and he walked out.
Police have linked the five offences which have all happened in Croydon, except for one in Brixton Hill.