An analysis of the cellphone circuitry in two package bombs intercepted last week suggests the bomb maker intended to delay any explosion until U.S.-bound planes carrying them were close to landing, U.S. officials told The Wall Street Journal.

Authorities intercepted the two packages, which were sent from Yemen, in the U.K. and Dubai after the U.S. was tipped off by Saudi intelligence that they were being shipped aboard UPS and FedEx flights. The packages carried addresses that had belonged to Jewish synagogues in Chicago but were long out of date.

Officials say they have strong evidence Yemen-based al Qaeda in the Arabian Peninsula, or AQAP, was behind the plot. The group's chief bomb maker is suspected in other recent attempts using innovative methods of hiding explosives. "There are very strong indications that AQAP is responsible for the recent cargo plot," a U.S. official said.

Officials cite design changes made to maximize battery life, and the outdated addresses, as signs that the terrorists intended to blow up the planes in the air and delay blasts until near the end of their journeys.

Read the entire story at wsj.com