Japanese prosecutors arrested ousted Nissan Motor Co boss Carlos Ghosn for a fourth time on Thursday, on what media reports said was a new case over improper payments made by the automaker to a dealer in Oman under his watch.

The re-arrest, which national broadcaster NHK described as a highly unusual move for someone who has been released on bail, marks the latest dramatic twist in the once-feted executive’s fall from grace.

Prosecutors arrested Ghosn on suspicion of aggravated breach of trust, NHK said, after visiting his residence in Tokyo early on Thursday and asking him to submit to questioning.

The arrest comes just a day after Ghosn pledged on Twitter that he would hold a news conference on April 11 to “tell the truth” about the allegations against him.