Today's decision focused on chief suspect Adel Habarra. The decision is to be reviewed by the country's grand Mufti, whose opinion is consultative.
A final ruling is scheduled to be issued on December 6.
The attack last year saw Islamic militants ambush two minibuses carrying off-duty policemen in a broad daylight near the border town of Rafah, days after security forces killed nearly 1,000 people in a crackdown on sprawling protest camps in Cairo by supporters of ousted Islamist President Mohammed Morsi.