FRESH AIR: Donald Trump has refused to release his income tax returns. This has left unanswered questions about his business practices and possible conflicts of interest between what’s best for his international businesses and what’s best for our country. My guest, Washington Post reporter David Fahrenthold, has found an alternate window into some of Trump’s finances. Since January, Fahrenthold has been looking into Trump’s charitable giving. His reporting has raised questions about ways in which the Trump Foundation may have violated the law. He’s found that Trump hasn’t always followed through on donations he’s committed to, and some charitable donations that Trump claims to have made from his own pocket actually came from money others donated to his foundation. Fahrenthold also discovered that Trump has sometimes requested that money owed to him be paid to the foundation, which may have enabled him to avoid paying taxes on that money. Fahrenthold has used crowdsourcing on Twitter to help him find information on whether Trump has fulfilled his financial promises to charities and how he’s used his foundation’s money. Fahrenthold’s Twitter account was described as one of the most surprise sensations of the election year by CNN media correspondent Brian Stelter. MORE