HONG KONG, Dec. 19 (Xinhua) -- Hong Kong police on Thursday arrested four people for money laundering and froze about 70 million Hong Kong dollars (nearly 9 million U.S. dollars) of funds, stressing that the gang was also suspected of funding violent incidents in ongoing social unrest.

Three males and one female aged between 17 and 50 were arrested in the morning, acting senior superintendent Chan Wai-kei of financial investigation division of narcotics bureau said at a press briefing.

Police seized 130,000 Hong Kong dollars in cash on the spot and froze about 70 million dollars at bank.

The people under arrest were found in connection with Spark Alliance, an online fund-raising platform for the current social unrest, which has collected about 80 million Hong Kong dollars in the past half a year.

Chan said the fund is possibly used as a reward to encourage teenagers to come out and join the social unrest as a receipt for the purchase of 3,300 supermarket coupons worth about 160,000 Hong Kong dollars were found. Police also seized two laser pointers, six arrows, and a lot of protective gears.

"Our action today was based on the suspicious financial transactions conducted by a shell company in the past six months as we found there were large cash deposits passed into this shell company," Chan said.

Chan said a significant portion of the money has been used to purchase personal insurance products, in which an individual is a beneficiary.

Chan said the police will continue to work with the Department of Justice for further action, including investigations into sources and destinations of the funds.