The president does not mean he can cover the sky with one hand.
In fact, the president is shackled by multiple forces – national news media are always on the lookout to dig up political scandals, the various major parties represented by the giant tycoons are never at peace, and there's the Supreme Prosecutors' Office, closely followed by the general public—
Inside the Supreme Prosecutors' Office, there exists the Central Supervision Department, which specializes in investigating politicians and high-level officials, with the function of preventing corruption and abuse of private power.
No wonder the prosecutor took notice when Christopher Simonson got involved with the murder case.
Using Christopher Simonson's critical illness as an excuse, the Presidential Palace refused the prosecutor team's request for investigation.