Note: I created a new account for this question because asking it on my regular account could probably lead to identification of the person it's about.
On one of the many other StackExchange sites, there is someone who I suspect is gaming the system by upvoting his own posts using two different accounts, positively commenting on his own posts using the two different accounts, using a second account to negatively comment on answers that compete with his answer on the first account, etc. I have already reported these suspicions, that's not what the question is about, this is just context (he/they still is/are active though).
Now, because of my suspicions, I performed a google search on the two different account names + a common location for them. This led me to what appears to be a personal website of at least one of the accounts. However, among the google results already there were some strange files on this personal website, which are highly likely not intended to be publicly accessible. Investigating further showed many more files that are publicly available on this personal website. I'm talking about things like:
- A signed contract for a house in pdf format
- Archives containing a bunch of source code (the person in question is a programmer), including source files with copyright notices of a company he works at / has worked at.
- Contact details, birthdays etc. of family, friends, other kinds of acquaintances
.bash.historyfile, which contains a long history of commands he has entered into his Linux-based computer. This file includes various raw-text usernames and passwords which he entered himself, links to porn sites he has been visiting/downloading from, etc.
- Various references to the name also used by the second account which I suspect he's abusing on StackExchange, and one explicit mention of using a second account (plus a link to something he's probably using to avoid detection by making it look like the two accounts are operating from different IP addresses).
My Question: Even though I don't particularly like the person due to the behaviour I have perceived, I do feel like I should somehow inform him that all this stuff is publicly available. He'd probably want to know and do something about it.
I don't know what the best way to go about that would be though. I could probably create an anonymous email account to send an email from. However, I haven't been able to find a place where he clearly publishes his email address (I did find various different email addresses in the files which I'm probably not supposed to have had access to though). I'd probably also have to explain how I managed to stumble into this stuff in the first place, but then he's likely going to be able to identify who I am; before finding these files I did already confront him in a comment from my main account that I've noticed his behaviour and don't think it's acceptable.
At the same time, if I'm already contacting him somehow anyway, it would also be nice to ask him to stop his cheating behaviour. I certainly don't want to come across as trying to blackmail him or anything; I have not and will not share his files with anyone else, but I still think he should be made aware that his behaviour on the site is not acceptable. Again, this is going to mean that he can likely identify my though.