Is it possible to find out ID identity?

Hello,

Couple days ago on some of PC-s inside of company someone was trying to access some of the PC-s but luckly we changed all passwords on time. I have seen ID number in log file, and when I added this ID to my list, I could see that user is online.

I have premium license, and a company with around 150 PC-s. It's really critical for me to find out atleast the IP address of that ID. Is there anywhere I can file a claim?

 

Thanks