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Someone with access to all or parts of President Donald Trump’s tax returns wants them made public. But who?

Tuesday's disclosure of two pages from Trump's 2005 federal returns marked the second time in the last seven months that portions of Trump’s tax filings have been leaked to reporters.

In October, The New York Times published a story based on a leaked portion of Trump’s 1995 state tax returns in multiple states, showing that he declared a massive $916 million loss that year that could have enabled him to avoid paying federal income taxes for nearly two decades. And on Tuesday, investigative reporter David Cay Johnston unveiled some details of Trump's 2005 federal income tax return on MSNBC's "The Rachel Maddow Show."

Trump promised during the 2016 presidential campaign to release his tax returns, but has repeatedly refused to do so, citing an IRS audit he has yet to show proof of.

Related: Trump paid $38 million in federal taxes

Here's what we know about how the leaks happened and what they tell us about who the leaker — or leakers — might be: