A local nomad has confessed to selling explosives that may have been used in the Sinai attacks, Egyptian police say.
Security forces say the suspect is claiming his buyers said the material was intended for smuggling into the Palestinian territories.
Egyptian investigators are questioning dozens of nomadic Bedouin in connection with Thursday’s bomb attacks in Sinai.
At least 32 people died in the blasts at a hotel and campsites in eastern Sinai, most of them Israelis.
The Hilton hotel in Taba, on Egypt’s border with Israel, was hit by the largest explosion, while two smaller blasts killed two people in Nuweiba.
The Egyptian security officials are quoted as saying a car used in the Taba bombing had been bought in Egypt – indicating that the attackers were probably Egyptian.
However, they are working on the theory that the explosives were smuggled by the alleged Bedouin suspects across the Gulf of Aqaba from Saudi Arabia or Jordan.
Israel has blamed al-Qaeda for the attack; both Saudi Arabia and to a lesser extent Jordan are home to sympathisers of Saudi-born Osama Bin Laden’s organisation.
Police say the detained Bedouin have been co-operating with authorities and have provided valuable information about explosives that may have been used in the attacks.
Sinai is inhabited by about 4,000 semi-nomadic people from about 10 Bedouin tribes.
Correspondents say they are known for mixing freely and peaceably with the tens of thousands of Israeli tourists who flocked to the eastern Sinai before the bombings.
The Bedouin are renowned for their knowledge of smuggling routes through the Sinai’s inhospitable desert and rugged mountains.
Security officials said if Bedouin were involved they would not have needed to use the peninsula’s tightly guarded roads.
Egypt is reported to want to send military or border police forces into the demilitarised eastern Sinai, which is currently restricted under the 1979 Egypt-Israel peace treaty, in order to help deal with security in the area.
Israeli rescue crews returned home on Sunday evening after finishing their work at the shattered Hilton.
After crossing to Eilat, the head of the team, Yitzhak Hillel, said the Jewish prayer for the dead at a memorial service for the victims.
Egyptian civil defence teams have taken over operations are the site of the Taba attack, as medical officials struggled to identify the remaining victims.
The Egyptian interior ministry has confirmed 11 Israeli dead, as well as eight Egyptians, two Italians and one Russian. Israel’s Home Front, an government internal security agency, said 13 Israelis had died.
Egyptian officials are reported to have discussed the attacks with officials from the Palestinian militant organisations Hamas and Islamic Jihad.
The discussions are not an indication that the two groups were behind the attacks, reports say, but the possibility is being explored that disgruntled defectors might have been involved.
Egypt’s most radical home-grown Islamic movement, al-Gamaa al-Islamiya, has condemned the attacks, saying they had no religious legitimacy.
Three previously unknown groups have claimed the attacks. One, the Martyr Abdullah Azzam Brigades, posted a statement on the internet on Sunday saying it was solely responsible.