Old or Unclear Photos
This is one of the easiest warning signs to spot early on in your communication with someone. If you notice that the person you're corresponding with only has photos that seem outdated or that have been taken from far away or from extreme angles, it's not unreasonable to suspect that she might be hiding something and probably does not look quite the same in person.
No Reliable Form of Contact
If the person you have met has a "Don't call me, I'll call you" policy once you have taken the relationship beyond e-mail, it may mean that he's trying to conceal his relationship with you from a wife or girlfriend. If you do manage to get his phone number but he insists on only texting and never answers when you call, that's another red flag. Anyone who has no encumbrances and is fully open to a new relationship would not want to put these types of unexplained restrictions on communication.
Vague Answers or Avoidance of Questions
While it's smart to avoid giving out a large amount of personal information to someone you have recently met on the Internet, if your online date is vague or completely avoids answering anytime you ask a question about her job, family or personal life, it may be a sign that there's something she does not want you to know. Before escalating the relationship, it's important to ask yourself how much you really know about this person and whether you're comfortable with her apparent discomfort when it comes to talking about herself.
One of the biggest red flags to watch for when meeting someone new is inconsistency in his behavior or in the stories he tells. If he claims to have an impressive education and credentials but his current situation does not seem to match up to those claims, he may not be telling you the truth. By the same token, some online daters will lie about their age or occupation initially, and then will reveal the truth to you later on after you have been corresponding for awhile. This type of behavior may make you wonder what else he is being deceitful about.
Insecurity and Possessiveness
If the person you have met seems overly curious about your activities, such as who you have been seeing or speaking with, this is a sign of a possessiveness that is unlikely to subside if you take the relationship offline. Constantly having to account for your whereabouts and to reassure your partner of your loyalty can be exhausting, so you will need to decide whether this type of relationship is actually worth pursuing.