What the hell you need a lawyer for? Since his IP is in Kansas, any one of you US citizens should be able to complain directly to police, and let them do the leg work. Bit trickier for us Brit's though.
lol! "Hello Kansas police? Yeah see this guy stole my Dogecoin..."
"Last night while I lay sleeping
In my house they came a-creeping
Somebody, somebody stole my doge"
(Rufus Thomas, haha)