Thanks to the Internet, tracking down a school chum or a lost love has never been easier. Besides search engines, there are online phone directories (www.infobel.com/teldir) and sites designed to connect people, such as www.friendster.com, www.classmates.com, and www.linkedin.com. “If the obvious sources don’t work, go backward to the person’s mother or sideways to a sibling,” says Kathleen Hinckley, a private investigator in Westminster, Colorado. For instance, finding a brother can help when a woman has changed her name. You also can search a national database of obituaries through a public library — funeral notices usually say where survivors are living and often give a woman’s married name. C.R. Brown, owner of Brown and Associates, an investigative firm in Orlando, Florida, says that if the friend is someone you grew up with, your best bet might be to go back to the old neighborhood and ask around. “Sometimes,” he says, “people who have been in business there for 20 or 30 years know everybody.”