The gang had threatened the owners on several previous occasions to blackmail them for money, without success, and last week they returned to the store, reports the Sydsvenskan newspaper.
"They went into the store and took it over. That is, they threw out the people working there and continued to run the store and sell goods. They hijacked a grocery store!" local police station chief Mats Attin told Sydsvenskan after his officers were alerted by the owners.
"They got in touch and we went there in plain clothes and sure enough, these four people were inside. They had been restocking shelves, and we've caught it on video. It went on for at least 24 hours," he said, incredulous. "I've been in Malmö for a long time, but never seen anything like this."
The men are in their 20s. One of them, thought to be the leader, has a string of previous convictions, reports Sydsvenskan. He is from Malmö's Seved district, where he and a relative are understood to have been responsible for much of the area's criminality.
On Monday Malmö District Court remanded the men on suspicion of aggravated blackmail and aggravated unlawful dispossession.