Already been done according to this article:
https://steemit.com/news/@bitcoinshirtz/monero-is-now-the-only-100-anonymous-cryptocurrency
BlockSci, a new blockchain analysis firm, has successfully traced transaction from beginning to end on both DASH and ZCash. This is bad news for these blockchain projects as their biggest focus and value add is anonymity. Now this is technically gone.
They claim to have been unable to trace Monero, but the agencies of government, like NSA, likely do not struggle 😆