If I called the FBI and told them they should investigate whether doorhinge voted fraudulently, only on my saying that I thought you did, what do you think they’d say? “Yes sir! We’ll open up an investigation right away and make witnesses testify under oath!”
Do you think that’s how it works? They would ask me first what indications I have that this happened, and if I have nothing at all, they’d politely tell me that they’ll make a note and keep it in their files, thank you very much.
Now compound that by imagining the source of the accusation is someone with a history of habitual lying.
Your demand for an investigation into Trump’s unevidenced claims is just ludicrous.