A charity that was given a donation worth thousands of dollars by notorious pharmaceuticals entrepreneur Martin Shkreli has said it is giving the money back on moral grounds.

Amid public outrage and ridicule over drastically raising the price of a life-saving drug earlier this year, Shkreli, who is now facing criminal securities fraud charges and questions about his finances, tweeted that he gave “millions” to charity.

But on Friday Community Solutions, a homelessness charity, said it will give back the entire $15,000 it received from Shkreli. A spokesman for the New York-based organisation Jake Maguire, said the donor’s business practices were incompatible with its anti-poverty mission.

“We serve people who depend on access to AIDS meds every day, and as an organization I don’t think we can keep this money,” Maguire said.

In January, Shkreli launched a charitable foundation that is run by his sister. The Shkreli Foundation website says it is “dedicated to helping people facing a variety of adversities.” It lists several donations, including one to Community Solutions and a $1m gift to New York’s Hunter College High School, where Shkreli was a student.

Shkreli’s “extensive research on life-threatening diseases had a profound influence on his philanthropic efforts,” the website says. A phone message left with the foundation was not returned.

At Hunter, which announced the $1m gift in March, Shkreli’s pricing decisions prompted a contingent of Hunter parents and alumni to demand his money be returned, according to comments posted on Crowdrise, an online platform that helps people raise money. Some have said the money should be at least used in part to finance seminars on bioethics. In October, a Hunter alumna created a page on the website to raise money and “foster a discussion with the school.“

No one from Hunter could be reached for comment on Friday. Other grant recipients, including a New Jersey hospital network and a California psychiatry professor, also could not be reached.

Federal prosecutors charged Shkreli, 32, with running a Ponzi-like scheme at his former hedge fund and a pharmaceutical company he previously headed, using money from new investors to try to repay investors whose money he lost.

Shkreli denies the charges and is confident he will be cleared of them, a spokesman said on Thursday. The spokesman said on Friday he had no information about Shkreli’s charitable donations.

The charges are unrelated to drug prices but added to the public uproar Shkreli caused in September when he and his then-company Turing Pharmaceuticals Inc raised the price of Daraprim, an Aids and cancer drug, from $13.50 to $750 a tablet.

Shkreli resigned as Turing’s chief executive on Friday.

Prosecutors sometimes ask charities to return donations tied to fraud so that the money can be distributed to victims. It is unclear whether Shkreli’s gifts stemmed from the alleged wrongdoing in this case. A spokeswoman for prosecutors declined to comment.

Shkreli, 32, told the New York Times before his arrest that he had given away more than $3 million, and he has used philanthropy to rebut people who call him selfish.

“Greed? I don’t own a car - I don’t even have a driver’s license. Our company is not profitable. My salary is $0. I give millions to charity,” Shkreli wrote on Twitter in October.

Community Solutions said it received Shkreli’s check in January, months before he rose to infamy.

“When it’s so clear, like this, I think our position is that the right thing to do is obviously just to give that money back. We try hard to make sure that our money is coming from places we’re comfortable with,” its spokesman said.

Shkreli became a Wall Street gambler at 17, received his first lawsuit at 24, was worth an estimated $100m shortly after turning 30 – and at this year achieved the title of “the most hated man in America”.

Reuters contributed to this report