Shoppers were left locked inside a rat-infested illegal store after staff fled at the sight of police.
Officers found the 50 customers, being held against their will, after spotting a man acting suspiciously attempting to close the shutters of a premises in Cheetham Hill, Manchester.
After detaining the man and unlocking the doors of the shop, a group of customers ran out.
Inside, officers from Greater Manchester Police's Operation Vulcan team, found more people who had been locked in rooms on the second and third floor.
Excessive amounts of rat urine and faeces was found all over shelves, clothing, underwear and make-up that was being sold at the store.
In the basement, officers say they could not see the floor for boxes and bags full of items which would be sold after being stored in unsanitary conditions.
They discovered "incredibly dangerous infrastructure" and signs of exploitative labour, including an underground homemade air conditioning system the staff had made by drilling holes into the pipes on the ceiling.
It has taken the Operation Vulcan team two days to bag an estimated 20 tonnes of replica clothing, shoes, perfumes and make-up.
It comes after officers found a group of 30 shoppers trapped inside another store on the same street on 6 December.
Detective Superintendent Neil Blackwood said: "The state of this building was disgusting and so structurally unsafe.
"My team found members of the public trapped on the top floor with no means of escape.
"This isn’t the first time we’ve had to rescue members of the public from these buildings, but I urge people to think twice about entering these shops.
"With our presence increasing, the shop owners are becoming increasingly nervous and quick to lock the doors, no matter who is inside.
"By entering these shops, not only are you putting yourself in danger and at risk of the volatile staff, but you're funding serious organised crime which is having a devastating impact on the local community.
"These people do not care for your welfare; they’re simply trying to make some quick cash."
David Minto, Protection Manager at Greater Manchester Fire and Rescue Service, said: "Our fire safety inspectors attended this property and deemed it so unsafe, a prohibition notice has been served.
"Together we’re working hard to rid Greater Manchester of this illegal and dangerous activity that blights communities."
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To know...