The fact that Israel is so interested means that this guy is an Israeli agent. The Egyptians are known for their pursuasive questioning techniques.. Even the CIA used to send hard cases to Egypt for questioning. Let the Egyptians give this suspicious character a thorough questioning to see if he is an Israel agent. This is the most important thing for Israel. If he is not, then make the trade. if he is, then...that is another matter completely.
U.S. State Dept. condemns 'vicious terrorist attack' that killed Palestinian infant (Haaretz)
from the article: Report: Israel offers prisoner exchange for Ilan Grapel