GTA San Andreas Interdiction

CJ asks Toreno about his brother, Toreno explains he is in a prison upstate and will be looked after. Toreno then says a precious cargo needs collecting.
Get in the buggy outside and head to the marked location, pick up the rocket launcher and head to the top of the mountain.
Once there CJ will light a flare and a helicopter with the contraband will arrive, followed by some others that need to be destroyed. Collect the package that is dropped and take it to the garage in Las Brujas.