When two mother-daughter pairs were murdered in early 2009 in Largo, Maryland, local detectives and an FBI profiler declared the killings unrelated—because, police have now realized, they were duped by a well-read serial killer with two master's degrees whose extensive research had taught him how to throw detectives off track. The killer, whose name is not being released, will be remembered as "one of America's most infamous killers," a Maryland police chief says.
By studying books about forensic science, the killer learned how to clean up his crime scenes. He also intentionally changed his killing methods from victim to victim so detectives wouldn't think his crimes were the work of the same person, the Washington Post reports. Besides the four Largo murders, police suspect he may be linked to other crimes in Washington, DC, Texas, and Florida. The man is currently in police custody on weapons and sexual assault charges, but has not yet been charged with any murders.