Ling Jihua, the one-time top aide to former president Hu Jintao, is being investigated by the Communist Party's anti-graft watchdog, it said on Monday. 

Ling, 58, was under investigation for "suspected serious disciplinary violations", a term that usually refers to corruption, a statement read. 

The announcement comes two years after Ling's political career was dealt a major blow with the controversy surrounding the death of his son Ling Gu in a Ferrari crash in March 2012.

It marks the fall from grace of a man poised to join to highest levels of power in China prior to the fatal accident.

Members of his well-connected family have also been probed in his home province Shanxi over allegations of graft.