[TOMT][BOOK][2000s–2010s?] Kids chapter book set at the Grand Canyon where a guy falls/dies in a cave?
I’m trying to remember a kids/middle-grade chapter book I read years ago.
What I remember (possibly imperfectly):
It took place at/around the Grand Canyon (I’m pretty sure actually there, not just a canyon)
There were kids/teens, possibly friends on some kind of trip
I remember a scene involving a cave, and I think a man/guy gets pushed or falls out and dies (might have been accidental?)
One of the kids may have used the online username “Nodnarb” (or something very close to that). I think it was an internet/screen name.
I vaguely remember the main character possibly being named Brandon, but I could be completely wrong on that part.
I read it when I was younger, probably elementary or middle school age. It felt like a normal middle-grade mystery/adventure novel, not fantasy.
Does this ring a bell for anyone, or am I combining multiple books in my memory?