The surveillance footage, obtained by the Aftonbladet newspaper, shows grainy pictures of men carrying automatic weapons and wearing black hoods and black-and-white masks with skull imagery on them.
One image caught by the camera shows one of the shooters from behind. He is wearing a vest that has reflective stripes on it and the word Polis (Police) in large letters.
“He had on a police vest and something that I think was a Halloween mask,” one witness, who escaped unharmed, told the newspaper. “Then he took aim at us and shot.”
The two murder victims were 20-year-old Swede of Serbian origin who was a DJ at the bar and due to start university in London this year. The other victim was a 25-year-old man who press reports said was a leading figure in a local gang with string of convictions, including drug offences, and who had only recently left jail.
Police suspect that the shootings were gang related.
Three men were arrested for serious firearms offences and their possible involvement in the shooting is being investigated, although no direct connection to the crime has been established.