Trump Foundation was never legally certified to canvas money during its 29-year existence

Republican presidential candidate Donald Trump's charitable foundation reportedly has never obtained the legal certification required by the state to seek contributions from the public. Under New York state law, any charity that solicits more than $25,000 (£19,000) a year from the public must obtain a particular kind of registration beforehand, which the Trump Foundation failed to do, reports the Washington Post.

Charities as large as Trump's must also submit to a rigorous annual audit that tracks money spent. Tax filings show that in each of the past 10 years for which there are records, the Trump Foundation raised more than $25,000 from outsiders.

The filings do not reveal whether the donations amounted to solicitations under law, but there is "strong evidence" that they did in "several cases," according to the Post.

The Trump Foundation set up a website early this year to collect donations that it promised to pass along to war veterans, and has collected $1.67 million (£1.29m), according to the site.

A source in New York Attorney General Eric Schneiderman's office, which is investigating the charity, confirmed to ABC News that it never obtained the necessary certification to solicit money from the public during its nearly 30-year existence.

The Post has uncovered a string of anomalies in the Trump Foundation, including discoveries that some donations claimed to be handed out are missing, that money was donated as a political contribution, contrary to IRS regulations, and that money was spent on personal items for Trump, including a painting of himself.

He also may have used hundreds of thousands of dollars from the foundation to settle lawsuits against Trump business operations. In addition, Trump had not donated any money of his own to his foundation since 2008, according to the Post.

If Schneiderman determines that the foundation raised money in violation of the law, he could immediately order the charity to stop soliciting funds.

Schneiderman could also move in court to force Trump to return money that his foundation has already raised. There was no immediate response to the Post's requests for comment from Trump nor Schneiderman, the paper reported.

The recent discoveries concerning Trump's charity is ironic given that the candidate has made the Clinton Foundation, and what he calls its influence peddling, a key attack of his campaign.

The Trump Foundation was established by Trump in 1987 to give away the proceeds of his book The Art of the Deal. Trump gave a total of $5.4m (£4.2m) to the foundation between 1987 and 2006, according to the Post.

Tax forms for the foundation list Trump as its president and Allen Weisselberg, the CFO of the Trump Organization, as the treasurer. As of 2006, Trump's three eldest children Donald Trump Jr, Ivanka Trump and Eric Trump have been listed as directors of the charity.