Israel established a precedent for that with the release of Samir Kuntar to Hizballah.
More on this story. “‘Schalit is Hamas’s bargaining chip’,” from the Jerusalem Post, July 19:
Hamas will not give up on any prisoner in negotiations to free kidnapped IDF soldier Gilad Schalit, Hamas Prime Minister Ismail Haniyeh said Saturday.
Speaking at a ceremony at the Islamic University in Gaza, Haniyeh added that “Schalit will continue to serve as a bargaining chip in our hands, and will in the end bring about the release of many prisoners, including prisoners with blood on their hands.”
Haniyah also mentioned the release of convicted murder Samir Kuntar, in the framework of last week’s prisoner exchange with Hizbullah.
“I spoke with Kuntar, and blessed him on his release from the Zionist prison,” he said.
The Hamas prime minister added that he had decided to grant Kuntar a Palestinian passport in honor of his release.