Trump in midst of gathering storm of investigations. Mar-a-Lago document inquiry is one of many.

When former President Donald Trump disclosed that his Mar-a-Lago estate had been searched by the FBI Monday, the action prompted an immediate question: Of the multiple criminal investigations now pending, which one was the FBI pursuing?

Sources familiar with the matter have since confirmed that the unprecedented law enforcement action was related to a continuing federal investigation into allegations that Trump removed classified documents from the White House when he left office.