A payjoin isn't a "private send"
Also what's with the link and the graph?
Bitcoin wallets can now have private sends.
https://cointelegraph.com/news/monero-transactions-japanese-authorities-arrest-18-scammers 
Discussion
Thank you. I will read further.
Looks like a good time to get if this is true. Avoid laundering millions quickly in Japan
Use and possession of Monero is illegal in Japan.
The Japanese in the original Nikkei article is extremely vague, the feds were in the scammers Signal chat and they knew Monero was being used.
Its possible they just found their suspect in possession of some. Thats their "following the movement of Monero."