You can read the BBC article and see how little it's based on, and per this write-up, it's based on even less than that. Perfect fodder for modern "history" channels on basic cable.
In recent days, a number of news sites that rely heavily on aggregation have posted stories about [the Democrat vice presidential candidate] reporting “allegations” that he sexually assaulted a minor while working as a teacher and football coach.
The clearly false claims stem from the prolific work of one man, a Twitter conspiracy peddler [with a blue check].
...
In September, he promoted an obviously fake story about a “whistleblower” at ABC News anonymously claiming the presidential debate hosted by the channel had been biased in favor of Kamala Harris. To back up the claims, he published a purported affidavit by the whistleblower, a poorly formatted and typo-riddled document