they probably fear putting his life at risk (further) by broadcasting it.
A Fox employee in Gaza, who declined to give his name because he was not authorized to release information about the incident, said the two kidnapped people were reporter Steve Centanni, a U.S. citizen, and a cameraman from New Zealand.
http://www.usatoday.com/news/world/2006-08-14-gaza-kidnapping_x.htm?POE=NEWISVA