A quick note before we get started: Many people in this world want to be left alone, and you should respect that—these tips are not intended to help you stalk an ex or relative who has made it pretty clear they never want to see you again. These are fairly global and disclose more personal details. Google is still the first, best step, when searching social media. Facebook, Twitter and LinkedIn are all well worth digging into, and in each case there are little tweaks you can make to your searches. Twitter has a people filter on its search, like Facebook does, as well as an advanced search page.
Aliases and usernames have become a big part of our personal online presence, and we often feel tied to them when we register for new sites and services. This can be a great was to build an online identity, but it can also make it trivial to tie our activity on various services together. There are plenty of free and paid services which search and monitor social media and email accounts by username. Pipl is a great example. It will rapidly scan popular sites and services for email addresses, usernames, names, and phone numbers to build a comprehensive profile of a person.
Find out if they are using Tinder or registered on any of the top 50 dating sites in the next 30 seconds. Enter the targets email and find out if they have a secret dating profile listed. AdultFriender, AshleyMadision,Fling.
He lies about friends on Facebook. Women whom he says he went to school with are strangers that he has been talking dirty to. It seems you already have your answer that something untoward is happening.