GoFundMe and other crowdfunding sites have taken a tough stance on campaigns for a man arrested following violence at a far-right rally in Charlottesville, Virginia.
GoFundMe removed some campaigns, saying they fell foul of its rules regarding hate speech and abuse.
James Alex Fields Jr, 20, is being held in police custody after a car rammed into a crowd of protesters.
One woman died in the incident, and 19 other people were injured.
GoFundMe had removed "multiple" campaigns for Mr Fields, a spokesman told Reuters.
"Those campaigns did not raise any money, and they were immediately removed," said director of strategic communications Bobby Whithorne.
Kickstarter and Indiegogo, fellow crowdfunding platforms, said they had not seen any campaigns in support of Mr Fields and a spokesman for Kickstarter pointed out that the site did not allow fund-raising for personal needs or legal defence.
Both platforms added that they were monitoring the situation.
A check by the BBC found no evidence of such fundraising efforts on any of the three sites.
There are several GoFundMe campaigns in support of victims injured while protesting against the white nationalist march.
However, there are at least two campaigns in support of those who marched at Charlottesville at an "alternative" crowd-funding site called Rootbocks, which uses the slogan: "No Censorship. No Limits."
One seeks to gather funds for Nathan Damigo - the founder of a white nationalist group - to bring legal action against the city of Charlottesville.
The campaign argues that Mr Damigo's First Amendment rights were "violated" when he was arrested at the event.
About $9,000 (£6,900) has so far been raised out of a $50,000 goal.
Other technology sites are closely managing the discussion of incidents at Charlottesville.
Facebook said it would remove links to an article on a neo-Nazi website denigrating Heather Heyer - the woman who died - unless links to the piece condemned it.
The site in question, the Daily Stormer, was also forced to switch domain registrars twice in 24 hours after GoDaddy and Google both expelled it from their services that allow customers to register web addresses.
Later on Monday, other tech platforms used by the site - including email newsletter provider Sendgrid and business software firm Zoho - said they had also terminated services.
Companies responsible for content posted on their websites were in a difficult position when it came to policing offensive speech, said Prof Eric Heinze at Queen Mary University of London.
"The problem is with Facebook [and others] you have these large platforms that basically replace the town square and public park," he explained.
"You're giving a private company a censorship function."
He added that while companies are within their rights to remove content that offends them, the action can still prove controversial.
"This issue is not a solved one, it's something our society will not be able to completely iron out in the foreseeable future."