At more than 310,000 likes, the official Black Lives Matter Facebook page has a sizeable following.
Yet as CNN has discovered, an imposter page, which uses the campaign's name, has amassed more than 700,000 likes.
The page is allegedly linked to a website owned by an Australian man, Ian Mackay, who has registered a number of sites related to black civil rights like blackpowerfist.com.
At least $100,000 was brought in via online fundraising associated with the Facebook page, for causes purportedly for BLM. However, according to the report, some of this money was instead transferred to Australian bank accounts.
Mackay told CNN he didn't run the Facebook page. It had a connected website which was registered under his name, but he "once bought the domain name only and sold it."
The web address was removed from the Facebook page when Mackay was asked about his involvement by a blogger, Jeremy Massler, last December.
Massler told Mashable via email he was blocked from the fake Facebook page after making that blog post, even though he never participated in the page. He also said there were commenters on the fake Black Lives Matter page and its associated group who expressed concern about the page's administrators.
"I certainly wasn't the first to notice. The real hurdle seemed to be getting a response (or even an acknowledgment) from Facebook about the issue," Massler said.
Black Lives Matter co-founder Patrisse Cullors told CNN she contacted Facebook about removing the page a few months ago, after suspecting it was fake.
Cullors added that fake fundraisers devalue the movement's work, and that it relies "on donors who believe in our work and our cause and that money will be used in a way that is respectful."
As it stands, the page has been taken down. A Facebook spokesperson told Mashable it had "developed several techniques to help detect and block inauthentic activity such as this," and that the social network's teams review reports of impersonators from the public.
Campaigns related to the page on Patreon, PayPal, Donorbox and Classy have also been shut down.
The revelation comes as Facebook CEO Mark Zuckerberg faces a congressional hearing on Tuesday, where he will be grilled on the platform's role in the Cambridge Analytica scandal.
Mashable has contacted Black Lives Matter for comment.