Local and federal investigators were combining efforts Thursday to determine why a cache of illegal fireworks exploded as it was being destroyed in South Los Angeles, injuring 17 people — including 10 law enforcement officers. A Los Angeles police bomb squad truck was destroyed from the blast Wednesday, and the vehicle remained on the street in the 700 block of East 27th Street near San Pedro Street Thursday morning as investigators worked to retain the integrity of the scene. We have exclusive videos below that were sent to us by local bystanders! The moment the explosion happened: (video uploaded on...