If the OP doesn't know how it happened he's at risk of it happening twice. It's process by elimination so a malware program's needed. OP didn't prove it's his cryptocurrencies so it isn't easy accepting what he's saying but I'm feeling sad if he's lost $165k.
Problem is also that is not going to be easy to determine if your device is clean or infected with something malicious.
I don't know how to prove that I own that wallet or that I lost the funds. However I did receive a voicemail from law enforcement today, I am certain I will be speaking with them tomorrow. So not sure how much more I should share. However I'd be glad to prove it's my wallet.