Taiwanese investigators on Monday questioned two more employees of a tech firm in a probe of the communications devices delivered to Lebanese-based terror group Hezbollah, which exploded in what appeared to be a series of coordinated attacks widely blamed on Israel.

Questions abounded over where the devices came from and how they were supplied to the terror group after hundreds of pagers and two-way radios detonated across Lebanon last week, killing at least 39 people and wounding nearly 3,000.

The New York Times reported that Israel had inserted explosive material into a shipment of pagers from Taiwan’s Gold Apollo, citing US and other anonymous officials.

Though Hezbollah and its patron, Iran, have blamed the attack on Israel, Jerusalem has neither confirmed nor denied involvement.

Taiwanese investigators initially searched four locations and questioned two people including Gold Apollo’s head Hsu Ching-kuang, who has denied producing the devices.

On Monday, the prosecutor’s office said it had questioned two more company employees.

“Today, it also directed the National Security division… to interview former or current employees of (Gold Apollo) as witnesses,” said the prosecutors’ office in Taipei’s Shilin district, where the company is based.

“The two helped clarify the case, and the whole case is under intensive investigation,” the prosecutors said in a statement.

Investigators have so far not named any of the witnesses, though Hsu was seen on Thursday shuttling between the office and his headquarters with investigators.

Gold Apollo had initially pointed the finger at its Hungary-based partner BAC Consulting KFT, which the Taiwanese company had allowed to use its trademark.

But a Hungarian government spokesman said BAC Consulting KFT was “a trading intermediary, with no manufacturing or operational site in Hungary.”

Taiwanese media had identified Wu Yu-jen, a representative of Gold Systems — reportedly connected to BAC Consulting KFT — as another person brought in for questioning last week.

The island’s economic minister had said they were “certain” that the exploding pagers in Lebanon were “not produced in Taiwan.”

Experts have said the batteries in the pagers are unlikely to have exploded. Rather, explosives were probably inserted into the devices before they reached Hezbollah, and then remotely activated.