The blast killed Mahmud al-Majzub as well as his brother Nidal.
On Thursday, Ilias Murr said: "Information received so far shows there is a strong possibility that the detonator in the booby-trapped car was set off by an Israeli aircraft monitoring his movements via a camera mounted on a truck."
Referring to daily violations of Lebanese airspace by Israeli aircraft, Murr said "the worst thing is that these violations enable the carrying out of terrorist operations in Lebanon, which is both frightening and dangerous".
He said it was "the first time in the 30 years Israel has been carrying out operations in Lebanon that an operation was executed at such a high-tech level.
"Nothing can provide protection in the face of this superior technique in terrorism and explosives."
The Lebanese army said on Tuesday it had broken up a cell linked to the Israeli secret service, Mossad, that had carried out attacks in Lebanon including the killing of al-Majzub.
It said the members of the cell had admitted their involvement in the Sidon attack, the killings in 2003 and 1999 of Hezbollah members Ali Saleh and Ali Hassan Dib, and the murder of the son of Ahmed Jibril, the Damascus-based leader of the Popular Front for the Liberation of Palestine-General Command.
Mahmud al-Majzub was a senior
Islamic Jihad official in Lebanon
The army also said it had seized the detonator that set off the device that killed al-Majzub, as well as explosives and electronic materials.
"It would seem that in the bombing that killed the Majzub brothers, the cell brought a booby-trapped door from Israel for the car used in the attack," the army said.
Mahmud al-Majzub, also known as Abu Hamza, was a top political official for Islamic Jihad in Lebanon. He had been responsible for operations "inside" the Palestinian territories, according to Lebanese security sources.
His killing sparked an escalating series of tit-for-tat cross-border exchanges between Israel and Lebanon that included rockets fired into Israel and retaliatory air strikes on fighters' camps inside Lebanon.