This is the simplest explanation, in that it involves only TB and nobody else (necessarily).
Weaknesses in this theory:
--Why did TB need to get gas before killing himself?
--Why did his friends not notice a change in demeanor?
--Why did he drive around all night without turning on his cellphone?
--No note?
--WHERE IS THE BODY??
It seems to me that this last question is the biggest weakness in the case. While I'm not going to say it would be impossible to kill yourself in a manner so that your body was not found, it does seem highly unlikely. I don't know of any reason a suicidal person would go to such great lengths to pull this off.
What would you add or subtract from this analysis?
This post consists of my opinions only.
Snipped for space-
Why drive around all night long? Was he visiting or driving by places that meant something to him? Trying to find the courage?
From what I remember, there was a small amount of blood found in his vehicle, along with a .25 casing. I could easily write off the blood (football injury, bloody nose, cut) if it was truly a small amount.
But why is there a bullet casing in the vehicle? Does/did TB have access to a .25? If it was suicide, one would think the body would be near the casing (if indeed it was a self-inflicted gunshot). But if the .25 is related, it seems that he would have had to shoot himself then walk a fair distance from the vehicle to not be found. Not ruling out the possibility, but I really don't want to imagine something like that happening.
Why are his belongings not in the vehicle? Why dump them at all? What was on them that he didn't want seen?
I can't imagine having friends willing to lie to cover up a suicide at all. But I think if they were lying, they would have said something like he caught a ride out of town.
Other than a potentially troubling Instagram post and a missing teen, I'm just not connecting the dots on suicide at all.
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My theory is that he was having issues with teammates on the football team. Either they were sabotaging him and forcing him to look bad so he'd lose his spot, or maybe there was tension and they just weren't playing well together.
I think there was either a whole lot of lying done by these two "friends" and possibly their parents. Or TB went to get gas and picked up another "friend". I'd like to know who on the football team as well as those he had contact with had access to a .25. I wonder if either of the friends he dropped off did?
Would those two friends cover for a third friend? Would a parent cover for their kid? Has anyone besides the two friends he was with verified that it was just the trio hanging out that night?
Was TB actually spotted getting gas or are they just using the debit card transaction as proof? I honestly can't remember now. Was there anyone with him if he was actually seen?
I don't think TB was driving at 4 am or if he was, it wasn't because he wanted to be.
I think whoever was with him forced him to turn off the phone so they couldn't be tracked.
I think a .25 is the ideal weapon of choice for a teenager wanting to scare/murder someone. Easy to conceal in a pocket/sneak it out of the house. Reasonably quiet, so no real risk of neighbors hearing the shot.
Murderer wouldn't want the body found. And probably more apt to dump belongings either because they tie them to the murder or they were looking for something in particular, or maybe just muddying up the case or trying to lead LE away from the location of the body.
It's a lot easier to move (and hide) a dead body away from the crime scene than it is for a dead body to walk away by themselves.
How do you feel about me answering all of your questions with a bunch more questions?!