Ronald K. Noble, a New York University law professor and the first American elected to head the International Criminal Police Organization — better known as Interpol — knows what it is like to be suspected of a crime.

The son of an African-American G.I. and a German woman, Mr. Noble said that when returning from his travels abroad, he is often stopped by U.S. Customs officers who see in him the profile of a globe-trotting criminal.