Hong Kong, July 30 (DPA) Seven people have been arrested in a loan shark operation in which borrowers were charged annual interest rates of 540 percent, police said Thursday.

A large number of documents, debtors information, bank cards and computers were seized when the four men and three women, ages 23 to 48, were arrested.

Police said the investigation started after a 28-year-old woman borrowed 8,000 Hong Kong dollars ($1,025) from the syndicate in 2007. She allegedly had to pay 1,200 Hong Kong dollars in interest every 10 days.

The woman complained to police after she was told by the syndicate that she still owed 70,000 Hong Kong dollars even though she had repaid more than 40,000 Hong Kong dollars.

The subsequent police investigation found more than 150 people had borrowed over eight million Hong Kong dollars from the syndicate. The group had advertised low-interest loans in magazines and internet discussion forums with no proof of income required.

Police believed income from these loans generated interest payments of more than 600,000 Hong Kong dollars every month.

The seven suspects face charges of lending money at an excess interest rate.