Will North Carolina be one of those places?
https://www.thisamericanlife.org/radio-archives/episode/606/just-what-i-wanted?act=2
The only fraud was Republican (paid volunteers, paid by the ballot to acquire absentee ballots that the voters then didn't receive, those voters couldn't vote because "they had already voted using absentee ballot") which sounds like the investigation is ongoing.
But as the end basically points out Republicans want more controls because those things are a determent to the Democrat vote.
For that reason he isn't investigating anywhere where he won. Just places that cost him the popular vote like California because like any great dictator Trump cares about popularity more than anything.