I stopped at the local cop shop and told them my story -- "How I hate to see abandoned bikes like this ravaged by "the elements"". They said to call this number ###-###-#### and tell them where it is. Then they will come by, remove the bike, and take it to some undisclosed location until someone calls that LEO shop and asks about their missing TREK. Same difference in my opinion. Just as well leave it there.
The decal just says that the bike is registered with some unidentified entity. ???
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I don't do: disks, tubeless, e-shifting, or bead head nymphs.