MANTECA — The federal Bureau of Alcohol, Tobacco, Firearms and Explosives is working with the Manteca Police Department to investigate a July 3 explosion that injured six teenagers attending a holiday party.Together, the two law enforcement agencies announced a $5,000 reward Wednesday for information leading to the arrest and conviction of whoever may be responsible for throwing an illegal explosive device over a fence into the backyard of a home in the 300 block of [...]