Twenty-five Egyptians were freed from a jail in southern Israel and taken to their country's border yesterday ahead of a swap for a US-Israeli citizen jailed in Cairo on suspicion of espionage.
The arrest of Ilan Grapel, 27, in Egypt in June set off new concerns in Israel that relations with the Egyptians would sour after President Hosni Mubarak was forced from office in February.
Mr Grapel's father said his son had been held in isolation in an unknown location. When they last spoke two weeks ago, he seemed to be "okay" and "getting fed", said Daniel Grapel.
Under a swap deal reached earlier this week, his US-born son was due to board a plane in Cairo yesterday and fly to Israel, where he will remain for at least two days before returning to the US.
Mr Grapel was volunteering at a legal aid group in Cairo when he was arrested on 12 June and accused of spying for Israel during the revolt that overthrew Mr Mubarak. Israel denied the espionage allegations, as did Mr Grapel's family and friends.