Thailand’s Supreme Court has removed Prime Minister Prasitha Thavisin from office, ruling that she violated the constitution by appointing a former prisoner as a minister.

The appointed minister was accused of bribery as a lawyer in 2008. It was never proven, but he was briefly held in contempt of court in that case.

Sritha is already the fourth prime minister to be removed by the court in 16 years. It is not entirely clear what exactly is going on behind the scenes. The BBC notes that in the past ministers have been allowed to stay in office with more serious convictions behind their names.

Press agency AFP and BBC I write that the initiative against Sritha comes from former members of the military-controlled Senate, which has significant influence over the court. A political party within the coalition close to the military will particularly benefit from this.

Thailand’s parliament must now find a replacement for Sritha, but it is uncertain whether the fragile coalition will be able to agree on a new leader.

The cabinet will remain in office on an interim basis until parliament approves a new prime minister. There is no time limit for parliament to fill the vacancy.