I had an interesting childhood during my summers living with my grandparents. They were huge supporters of foster care and housed many dozens of foster children well into their late 60s and I would always be their appropriate aged company.
Most were reasonably well behaved, but some were... well, different.
One brother and sister pair came along. My girl cousin would play with the sister, and the brother would come along with me. In a sparse New Mexican desert, we would look for horned lizards and diamondbacks that roamed the area. Some times I would explore the desert with him, but some days he would sneak off on his own.
One night, maybe at 4AM, he woke me up and told me he saw something he'd never seen before; a big deal for a guy who just a year ago was taken from his last foster family on account of domestic violence (I didn't know it at the time, but looking back it became obvious). I told him I would go look at it the next morning.
The next morning he led me down into a ravine, the tan sandstone pockmarked with three or four holes in a way I'd never seen before. At the base, this 11 year old pulled out a pistol from behind a small rock.
He offered to let me use it, a request my 10 year old self denied out of fear. He shrugged his shoulders as if to say "your loss" and fired two rounds into the air. The sound made me cower; fireworks were legal in this town year round, but the bang was unlike any sound I'd ever heard before.
We wandered the desert, a mile or so away from my grandparents' house, the foster child with weapon in tow. I only prayed he didn't fire it again, as the noise scared the hell out of me. As we walked toward an old, wind-worn building about a half mile away a man walked toward us.
He asked us if we heard a loud noise a few minutes ago and we lied (poorly I imagine, judging by my nervousness) and said we didn't. He narrowed his eyes and told us that someone had broken his window a few days ago and a few items were stolen.
The weaselly bastard child looked at the ground, then at me and darted. I followed suit in a kick of adrenaline and the fear of my grandmother's vicious sandal spankings. We ran for what felt like forever into the desert.
We didn't make it home until lunchtime thinking we got away from trouble. My grandparents stood at the doorstep waiting for us, telling us an odd tale from a neighbor about a couple juveniles causing trouble. They'd told my grandparents everything, scoured my foster cousin's room and found some stolen jewelry. He was sent to juvenile detention and I was confined to my room for the next two weeks.
It was the most thrilling, harrowing and disappointing day of my life and I hope I never experience anything like it again.
> TL;DR: Foster cousin stole from a house, found a gun in the desert, got him and I caught and went to juvy, never to be seen by me again