In his tweet, Flynn called the fake story a "must read!"
Both Flynn and his son, Michael G. Flynn, have come under fire for their tweets propagating fake news online.
In his tweet from Dec. 5, Flynn's son said the "Pizzagate" conspiracy theory — which falsely claims that a popular pizza restaurant in Washington DC provided top Democratic operatives with underage prostitutes — would remain a story "until proven false," despite authorities calling it a "fictitious online conspiracy theory."
The theory prompted Edgar Welch, a 28-year-old man from North Carolina, to "self-investigate" the restaurant and fire his rifle inside in the process.
Flynn's son had not deleted his tweet as of Wednesday.
While he was initially involved in helping his father with administrative duties, Trump's spokesperson later said that he is no longer involved with the transition.