[_Jim]

Or was the device already planted before he sold the car to her with a remote activation of some type already installed?

AGAIN, there will be charred REMAINS of some 'device' ...

I guess you people don't "burn your own trash" anymore -

- or you'd have a better idea of WHAT is LEFT after an attempt at incineration ...

[null and void]

And your explanation of it all is?

[null and void]

You are making the HUGE assumptions that (1) they have completed the investigation and (2) found nothing.

Ya don't think they'd maybe keep a FEW details secret, if for no other reason than to check the veracity of a confession?

Nah! Cops alway let the perps know just how close they are to figuring out whodunit...

[testforecho]

AGAIN, there will be charred REMAINS of some 'device' ...

I am sure that FBI arson investigators are going over the car very carefully. They haven't announced one way or the other if there was any 'device' found, as far as I know. There could be one in there, and they haven't gotten to it yet.

But, to forestall your objections, let's assume that there is no incendiary device or fuel container present in the car. If there are witnesses, who saw no one get out of the car, and didn't see anyone throw anything in there, then I would believe this is a highly unusual suicide.

Unusual because people don't burn themselves to death very often, and black middle aged women (to generalize here) don't cook up some accelerant laced gasoline and set themselves on fire to make it look like they were in an accident. Or to fool fire investigators into thinking they were killed. Still, statistical improbabilities do happen.