Mark pleaded guilty to attempted murder and was sentenced to two years supervision. As an article in the New York Daily News explained in 2009, "Long before there was a craigslist or dot-com dating, there were places where men and women who were too shy or busy to meet face to face could find romance.Calling themselves "matrimonial bureaus," these organizations were known mostly as the "lonely hearts clubs," and they flourished through the middle of the 20th century." It was in venues like these—print media such as newspaper classified ads and personal or lonely hearts club ads—that 20th century murderers such as Harry Powers, the so-called "Matrimonial Bureau Murderer," met their victims.The other teenager, Mark, apparently believed he was being recruited by some female Secret Service agent.The suicide-by-homicide failed and on May 29, 2004 John pleaded guilty to inciting someone to murder him and was sentenced to three years supervision.Electronic advertising has gradually replaced printed ads and the internet is now a venue where murderers who employ a similar modus operandi can meet their victims; in Schecter's Encyclopedia, the entry for "Ads" mentions internet dating and the use of internet ads by the so-called "Internet Cannibal" Armin Meiwes.
Robert Frederick Glass pleaded guilty to killing Lopatka and later died in prison while serving his sentence.
In a case that might be regarded as a quasi-consensual homicide, "John," a teenage boy from Altrincham, England, allegedly tricked another teenager into killing him using long conversations in an online chatroom.
Online chatrooms are also used, in some cases, to plan consensual homicides.
For example, in 1996, a Maryland woman, Sharon Lopatka, apparently agreed to be killed by torture and strangulation in a conversation with a man in an online chatroom.
Serial killers are murderers who target three or more victims sequentially, with a "cooling off" period between each murder, and whose motivation for killing is largely based on psychological gratification.Such killers have used forms of social networking to attract victims long before the advent of the internet.