He had, he said, married a woman who lived in the Israeli occupation zone in the far south of the country - the strip of territory held by Israeli troops since 1978 - and had been recruited by Israel on a visit to his wife's village.
It was unclear whether the man was a prisoner or a defector, but his information was specific. For months he had lived in the area north of Israel's occupation zone, amassing details of Hizbollah's movements and equipment. On a set of photographic maps provided by the Israelis, he had carefully marked the home of each Hizbollah member. He had communicated this information, he said, through an E-mail system that operated on Israeli- provided equipment which he kept hidden in the cabinet of his television set.
Amid the blood and rhetoric of this latest, wearingly familiar war in Lebanon, Hizbollah was sending two messages over its TV station: that the historical background to the conflict is being ignored - in some cases deliberately - and that the Israelis had been planning this operation for months, just as Hizbollah itself had been working out its own methods of confronting the coming Israeli assault.
This is the trap into which the Israelis have walked. Unable to damage Hizbollah from the air, they can only fight the guerrillas on the ground, where they will take casualties. And the Israeli Prime Minister, Shimon Peres, whose 29 May election lies like a foundation stone to the whole Lebanese assault, cannot afford Israeli casualties; only Lebanese ones. So how come the Israelis launched their blitz in the first place?
Officially, they attacked because Hizbollah was firing missiles at Galilee and because five Israelis were wounded on Wednesday; a woman among them was critically injured. Israel, however, is not anxious to remind anyone why those Katyushas were fired - because, yet again, a Lebanese civilian had been killed, in contravention of the 1993 Israeli-Hizbollah agreement that was intended to spare civilians from being targeted in the south Lebanon war. Indeed, the list of civilian casualties in southern Lebanon is infinitely higher than the Israeli casualties of Hizbollah Katyushas in Galilee, a fact which the Israelis are again not eager to publicise.
Research shows that over the past 36 months, an Israeli tank at Nabatea al-Faqar has killed seven civilians, including three women, with flechette shells, that an Israeli mortar battery has killed a five-year-old girl and a young woman in the village of Shaqra, that a helicopter gunship has killed two young men building a water tower in Yater and that an Israeli jet has killed two families of 10 people in a house between Zahrani and Nabatea. Flechette shells are particularly deadly - hundreds of tiny steel arrows sprayed from a proximity shell that explodes just above head height and is designed to cause maximum casualties. The five-year-old bled to death in the street outside her home after the shell cut her legs off.
There was no talk of "terrorism" after these deaths. The Israelis said they would hold a military inquiry into the first Nabatea killings but it never took place. There was talk of the killings being a "mistake". The Shaqra deaths went unexplained. The Israelis said that the bombing at Nabatea and the Yater killings were also an "accident" - the same word they used to describe the killing of a Syrian army major in Beirut on Friday (though not, oddly, of their killing of a young woman on the coast road). At least 12 other civilians have been killed by the Israelis in southern Lebanon in the same period.
After most of these incidents, Hizbollah unleashed Katyusha rockets onto northern Israel in retaliation - adopting the very same policy of an eye for an eye and a tooth for a tooth which the Israelis had been using for more than 20 years. If the Israelis did not kill or wound civilians in southern Lebanon, Hizbollah confined its attacks to Israeli soldiers and their militia allies within the south Lebanese occupation zone, offensives which were, in effect, permitted under the 1993 agreement brokered by the US, Syria and Iran.
Last weekend a young boy was killed by a bomb in the village of Bradchit, and Hizbollah blamed the Israelis. Mr Peres denied Israeli responsibility, but Hizbollah did not believe him and fired 24 Katyushas at Kiryat Shmona. Only after an Israeli soldier was killed in the occupied zone the next day - a death that would later be lumped together with the Katyusha casualties and condemned by the Israelis as an act of "terrorism" - did the Israelis launch their military offensive against Lebanon.
Now both sides are trapped in combat yet again. Hizbollah has expressed its enthusiasm for just such a battle, while the Israelis have attacked in a more gingerly fashion. Perhaps Mr Peres will call for a resumption of the 1993 agreement. If not, he will be forced to keep his army in action into the election campaign, and that's not how you win elections.