Similarly, Hezbollah officials seem uneasy when discussing the group's links to Iran.
A Hezbollah official said the incident was meant to provoke the group's members.
Residents now say a Hezbollah official may have been living there.
Hezbollah officials who were asked about the letter said they had no recollection of it.
Hezbollah officials could not be reached Tuesday night for comment.
On Wednesday, opposition leaders met with Hezbollah officials to coax the group to join their effort, but to little avail.
Hezbollah officials say that the group distinguishes between Judaism and Zionism.
Hezbollah officials insisted that the movement of the arms did not violate the militants' accord with the government.
Hezbollah officials say they lost 1,200 fighters over the years, and yellow roadside markers are being put up at the spots where they fell.
Hezbollah officials in Beirut and Iran were expecting the arrival of a group during the same time period.