Yi made a surprising appearance at a Marxism forum held in Harbin, capital of the northeastern province of Heilongjiang, in November, magazine reported this week. He gave a keynote speech outlining domestic studies of Neo-Marxism in eastern Europe, according to the magazine.

A photograph printed with the report shows Yi at the centre of over 100 participants for a group shot.

This was Yi's first known appearance at a public event since he became one of the first senior party officials dismissed after party chief Xi Jinping took power in late 2012. 

His sacking came shortly after a lengthy account written by a female researcher in his department detailing an extramarital affair between them was published online, sparking wide public uproar.

“The lengthy account also included scenarios that Yi allegedly received both sexual and money briberies, but the authorities appeared to have never bothered to launch any investigations into the allegations,” Li said in an interview with the on Thursday.

Yi, a Marxism theorist, is rumoured to be the originator of the political slogan “The three confidences”, which argues the Communist Party’s leadership and its members must have complete belief in its “political route, theory and system”.

The slogan has become one of President Xi Jinping’s favourite sayings in the last two years. 

Thousands of Party officials have been investigated, sacked and prosecuted across the country in Xi's sweeping anti-corruption campaign which has so far shown no signs of letting up. While a growing number of these fallen officials are being accused of adultery by Party investigators, alleged sexual misconduct is usually tagged on to more serious accusations such as bribery, embezzlement or abuse of power, and very few officials appear to have been sacked for adultery alone.