Hong Kong (CNN) Hong Kong police say they have frozen about $9 million in funds raised by anti-government protesters, and arrested four members of a prominent fundraising group on allegations of money laundering.

Chan Wai-kei, the acting superintendent of the Hong Kong Police Narcotics Bureau's financial investigation division, said Thursday that police also seized about $16,700 in cash, 3,300 supermarket coupons, two lasers pointers, six arrows and "a lot" of protective gear. The four were taken in on money laundering offenses, Chan said.

Chan said the four suspects were connected to the Spark Alliance, a nonprofit formed in 2016 that helps arrested protesters to pay their legal fees. The group has raised $2.3 million in donations in the past six months, police said.

Over 6,000 people have been arrested during more than six months of political unrest in the semiautonomous Chinese city. Many face charges of rioting, which is punishable by up to 10 years in prison.

Police allege that some of the donations to Spark Alliance were diverted to a shell company, and some were used to purchase personal insurance products. One of the four people arrested is the beneficiary of the insurance policies and the owner of the shell company, Chan said.

Read More