Wolf check-in #64 is a paper note in the Fallout 76 update Wild Appalachia.
Location[]
The note is found in Lewisburg, in a cooler behind a house with a plastic flamingo in front of it. It is obtainable during The Lowe-Down.
Transcript[]
Wolf. Check-in #64.
Blacksheep has failed to report in. This was his final warning.
Bo-Peep is dead. Possibly related to Blacksheep.
I'll be conducting a removal today.
ATTN: Operatives reporting in: an ID Card and further instructions will be required. Bo Peep had a small monitoring station to keep tabs on Blacksheep. You should be able to find what you need there.
P.S. - Apologies, but I'll be requiring a clean-up at this site as well.