I Heard about multiple gangs targeting bitcoin exchangers, sellers, and people who own a lot of bitcoin.
Be aware of the fake 500 euro notes trick, that's going on in Europe. and be aware of who you deal with, because if the wrong people have the knowledge of you owning a lot of bitcoin or any crypto, they can easily trace you.

Shitty that these things are happening, my personal opinion for the safest way with local transactions would still be bank transfer, and use ESCROW until funds or bitcoins are released.
Over the counter trading with a registered company, or with someone from a known group.