A darknet lead on Base begins with a 0x string, and that string alone proves nothing about the network. Write down the address and the word Base together, because the same characters are valid on Ethereum.
First pass on Base
Run the free check with Base selected. A nonzero transaction count tells you the account has history worth opening in the public explorer. A zero count with a balance points to a wallet that only received funds.
Keeping the trail clean
Every counterparty you add to the trace needs its own network label. Base and Ethereum accounts can share one address, so an unlabelled hop is a gap in your own record.