UNABLE to make an arrest in the case of the smashed statues of saints in Roman Catholic churches in Brooklyn, New York police detectives have consulted with a fellow who was once one of their own, the psychological profiler Raymond M. Pierce, and if you think Mr. Pierce is going to speak about an ongoing investigation, you are a person of extraordinary naivete.His classes at the Police Academy -- where he makes politically incorrect jokes about the 400-pound murder victim found ''beached'' in her apartment, or reveals that the Son of Sam killer, David Berkowitz, returned to his crime scenes for sexual satisfaction -- are far more entertaining.''You look at the overview of the forensic and behavioral information present at the crime scene to develop a list of the characteristics of the offender as we would have if we had a friend of the offender giving a basic description,'' Mr. Pierce says, in the somewhat stiff language he sometimes uses with people who have never been on the job.If, however, you want to get some idea of what a psychological profiler does, Mr. Pierce, founder of the Police Department's Criminal Assessment and Profiling Unit and one of a handful of people trained in profiling by the F.B.I., will be glad to give you an idea.