A lonely hearts killer is someone who tries to find other people (especially women) through online chat rooms or dating websites, then meets and kills them. These kinds of people use deception and lies to get people to trust them, and they might pretend to be someone they're not in order to gain someone's trust so they can target them. It's important to be careful when talking to people online and to never agree to meet someone in person if you don't know them well. It's also important to be aware of anyone who seems suspicious or who is overly pushy or persistent about wanting to meet up with you.