Missing-Person Cases: A Balancing Act for Police
Missing-person cases require balancing act by police, who come under pressure from distraught families who feel that not enough is being done but who are reluctant to deploy limited recources in opening investigations when they know that most missing people eventually turn up; last year, 876,213 missing-person cases were reported to Federal Bureau of Investigation by local police agencies after calls from frantic families or friends; but there were even more cases--882,163----in which missing person was found or, in many instances, simply turned up; these figures demonstrate how unusual it is that Washington, DC, police have been engaged in such intense search for Chandra Ann Levy, government intern who vanished at end of April; photo (M)