More than 70 websites promising unrealistically high returns on bitcoin investments have been shut down by the New York County District Attorney's office.

As originally reported by Bloomberg News, 73 sites were taken offline on 16th January by the office, including BitcoinHYIP.org and others owned by a company called YouYou Finance.

The defendants are accused of securities fraud and intent to commit fraud, as well as larceny charges, according to documents provided to CoinDesk. The investigator explained the background of his investigation into high-yield investment schemes based on bitcoin, as well as how the office went undercover and used the services.

The complaint read:

The office determined that BitcoinHYIP.org belonged to YouYou Finance, which owned dozens of other similar sites.

The complaint, filed on 26th January, details how the district attorney's office first began looking into websites targeting bitcoin investors in July.

Notably, the document states that, in the case of investment schemes, bitcoin can be interpreted as acting as a type of security, arguing that "by seeking investors willing to invest bitcoins...these websites were using bitcoins as a security."

As part of its investigation into BitcoinHYIP.org, investigators went undercover and deposited 1 BTC with the website in August. The complaint notes that the defendants, prior to the payment, assured investigators that their investments were safe and their returns guaranteed.

The filing continues:

Other elements of the report include a blockchain data analysis suggesting that bitcoins sent to the websites were never returned to their originating addresses.

The official complaint can be found below:

Complaint - Bitcoinhyip.org and Youyou Finance

Images via BitcoinHYIP.org, Shutterstock