The New York Times wasn't the only news outlet to receive documents from Donald Trump's tax returns. But they were the only ones to successfully vet them.

Around September 23, the day a manila envelope with a Trump Organization return address showed up in the mailbox of Times Metro reporter Susanne Craig, a similar envelope arrived in the inbox of New York Daily News editor-in-chief Jim Rich.

Both envelopes contained three pages from Trump's 1995 income tax returns, which showed that the Republican presidential nominee had declared a $916 million loss that may have enabled him to avoid paying any federal income taxes for 18 years.

Related: Why Donald Trump doesn't have a case against The New York Times

The Times immediately set about vetting the documents and hired tax experts to analyze them. Craig brought in her reporting partner David Barstow, a three-time Pulitzer Prize-winning investigative reporter, as well as colleagues Megan Twohey and Russ Buettner.

But a source at the Daily News told CNNMoney that their paper was unsuccessful in locating a tax expert who could verify the documents.

"We received [the documents] around the same time... but were unable to track down the preparer or verify the veracity of the documents through other attempts," the Daily News source told CNNMoney.

When the Times broke the story on Saturday night, the Daily News was left scrambling.

On Sunday, the Daily News published a report on the Times story that cited the competition throughout, while noting in the third paragraph that the documents in questions "were also obtained by the Daily News."