The new probes represent an aggressive variation on efforts to use financial documents to take down opponents.

President Donald Trump has called on Federal Reserve Governor Lisa Cook to resign amid a claim by a top administration official that she may have engaged in so-called mortgage occupancy fraud by falsely labeling a secondary home as her primary residence to get better loan terms.

Three government officials have recently been accused by the Trump administration of committing mortgage fraud. What constitutes mortgage fraud? And what are the consequences for committing such a crime?