1.   Tensions only got worse not long after, when a homemade explosive injured four police officers just yards from the girls and their parents.

2.   Police spokesman Justo Ramon Zamora said four anti-riot police were injured by explosives fired from home-made mortars Monday.

3.   The following year, a Unabomber explosive injured Percy Woods, then president of United.

4.   Increasingly sophisticated and sometimes making a noise as loud as a bomb, the explosives injure dozens of people, especially children, every year.