Until last year, Zou was an assistant professor in the department of neuroscience and cell biology at the University of Texas Medical Branch in Galveston. A department administrator said that his contract, which expired in August 2009, was not renewed in the wake of "massive layoffs" after Hurricane Ike.

Zou returned to his native China in July 2009, leaving no forwarding address, says the administrator. He could not be reached for comment.