Tel Aviv shooter Nashet Melhem, 31, is believed to have escaped into the Palestinian Authority, according to various media reports.
After an intensive manhunt in the city, security personnel have reportedly come to believe Melhem was aided in his escape to the PA by friends he made while previously incarcerated.
A gag order has been clamped on any further details of the investigation.
The Israeli Arab suspect is accused of opening fire on partygoers at the Simta pub in Tel Aviv last Friday on Dizengoff Street.
Two people were killed and eight others were wounded in the attack.
The shooter then allegedly hailed a cab and escaped – but subsequently murdered Israeli Bedouin taxi driver Ayman Sha’abi as well before fleeing the city altogether.