1.   Police based their suspicion that the explosive could have come from the mainland on their experience with similar explosives in the past.

2.   Police said they were investigating how so much explosives came to be stored in a home in a residential area.

3.   The IRA denied any involvement in that incident, but security sources believe the explosives came from one of their stockpiles.

4.   Police are now trying to find out where the explosives came from.