So, Backes thinks Frazier was driving Oswald to work every morning. But why, if he thinks that, hasn't he gone to Frazier to find out? Doesn't he trust Frazier? Or does he think Fraizer would lie? He's never written badly of Frazier. So, why doesn't he go to him and ask him? And if he can't do that, then why doesn't he go to Debra Conway because I know he has contact with her.
And, Debra Conway has very close contact with Frazier. They're thick as thieves. In fact, they are so close and have been for so many years, that surely she knows whether Frazier claims to have driven Oswald to work. So, I'm sure she could tell Backes what he wants to know without even having to go to Frazier.
But, if so, I know what she's going to say: that Frazier did NOT do that; he did not drive Oswald from Oak Cliff to work. The reason I know that is because I have listened to Frazier. And when asked about his "friendship" with Oswald, he makes it clear that they really weren't friends. He says that they didn't do ANYTHING together outside work, except for those drives to Irving. That was it. Nothing else. They never even ate together. He is so adamant about the fact that they didn't do anything together except for that one specific thing, that if he had driven Oswald to work every day, it would amount to a bold-faced lie.
Granted, it would be a very big find to uncover that Frazier was driving Oswald to work every day. It's so big, it's hard to imagine how he could have kept it secret for over half a century. But, I rate the chances of Frazier revealing that he did that at: zero.