Is it possible to trace on XMR blockchain?

[Crypto Library]

We all know that XMR, Zcash are popular among privacy coins, and at the same time we also know that in the case of privacy coins, when we make a transaction, the wallet address, transaction amount, etc are hidden.
Basically, in the case of other blockchains, transactions such as those that are publicly visible on the blockchain aren't visible in the case of these privacy coins. Now my question is that if money laundering is done using XMR or Zcash, how are they identified?
Since no transaction or address of the blockchain can be identified, then what technology is used to identify them?
Or is it never possible to identify them if you use XMR? 

[Charles-Tim]

Or is it never possible to identify them if you use XMR? 

Monero transactions can not be traced.

But people should not think they can be 100% untraceable to the government. There could be just a slight mistake from the person. I still remember few years ago that a monero transaction was traced and linked to someone. No one knew how it was traced and not definitely through the blockchain but probably through the person's mistake.

[Crypto Library]

Or is it never possible to identify them if you use XMR? 

Monero transactions can not be traced.

But people should not think they can be 100% untraceable to the government. There could be just a slight mistake from the person. I still remember few years ago that a monero transaction was traced and linked to someone. No one knew how it was traced and not definitely through the blockchain but probably through the person's mistake.

Can you please more elaborate on the incident like any source where I can see the details? Here my question is how is it possible to trace them if you don't even know the wallet address or the amount?
In this case, I think it's not possible to know anything about it until you get access to that person's wallet.

But yes, I understand at least this much that the government of their country can catch those who commit money laundering or those who are associated with crime, if they want, but not through Monero tracing, but when that person spends his money, like when he spends the money, the government can basically catch him if they investigate where his money comes from.

[Charles-Tim]

Can you please more elaborate on the incident like any source where I can see the details? Here my question is how is it possible to trace them if you don't even know the wallet address or the amount?
In this case, I think it's not possible to know anything about it until you get access to that person's wallet.

This is an example that I found out about which was a post in 2024: https://bitcointalk.org/index.php?topic=5509696.msg64550340

I was unable to see the one that I am referring to because I thought I also commented on the thread at the time, but maybe it is as there are some threads that I may read and not join in the discussion.