Two people have been charged with stealing 50,000 charity bags of clothing left on people's doorsteps.
South Wales Police said they discovered the bags on an industrial estate in Cardiff after a tip-off from the public.
A man, 24, and a woman, 19, both Lithuanian nationals, have been charged with theft offences. Three others have been arrested.
South Wales Police said the haul was the work of an "organised crime group".
Police said the stolen bags - enough to fill six large shipping containers - were probably headed to an eastern European country and the contents sold for "massive profit".
The two people charged were arrested in Treorchy, Rhondda, after members of the public reported suspicious behaviour.
The subsequent police investigation led to the bags at Wentloog Corporate Park in Rumney, Cardiff.
Three other Lithuanian nationals, two men aged 30, and a 48-year-old woman, have also been arrested and are being questioned by police.
Det Ch Insp Phil Jones said: "This haul is likely to be the end result of weeks or months of work by the organised crime group, and it looks as though we have managed to intercept the goods just before they are transported away, most likely to an eastern European country.
"What this does show is that without realising it, so many people are lining the pockets of organised criminals who are very likely to be linked to other crime. People need to be mindful of this when giving to charity.
"We have had reports in the past of flyers or bags which mimic genuine charity bags being left at homes.
"We also know that bags left out for charities have been stolen.
"Our message is, please keep giving vital help to charities, but give with care and check your donation is going to those in need."