Trump tweets to claim he 'turned down' Robert Mueller to head FBI right before he was appointed to investigate collusion

President Donald Trump now claims that he "turned down" Robert Mueller to head the FBI "one day before" he was appointed special prosecutor to look into Trump's collusion with Russia in the 2016 presidential campaign.

Trump also claimed that the men have a "very nasty & contentious business relationship."

Mueller led the FBI for more than a decade following the 9/11 attacks. He served beyond the normal 10-year term at President Obama's request before finally retiring. He was appointed special prosecutor in May 2017 at age 72.

Previous reports attributed to anonymous sources had said that Mueller had interviewed with Trump the day before the appointment, but not that Mueller has been "turned down."

Trump did not nominate the current FBI director until several weeks after Mueller was appointed to investigate his collusion with Russia.

It was unclear what the "nasty & contentious business relationship" referred to as Mueller spent most of his career in the public sector.