Experian, one of the world's largest database marketing companies, will launch an Internet-based fraud detector. Called Authoricheck, the detector will let companies know whether potential online business clients have characteristics that indicate fraudulence. Authoricheck can be used to determine whether a potential client is operating from prison, for example, or using the Social Security number of a dead person. Authoricheck is in beta and will launch within the next several months, said Christine Martin, senior marketing manager. Experian has a host of financial clients including Morgan Stanley & Co. and Citigroup.