Moai statues
You can find five Moai statues during the Intel Operative Rescue side mission.
On top of the tower after the first five enemies and the helicopters circle around to the warehouse area.
Inside Chico's cell.
In the watchtower on the corner of the administrator building, where the guard tries to fire a rocket launcher.
Get off the helicopter and kill all of the enemies at the base. Run to the rocket launcher. Wait for the gate to open, then allow the tank to pass.
The Moai statue can now be found at the bottom right corner of the gate. It must be collected before the gate closes.
Search the square roof at the base of the large tower that the other helicopter blows up. You may need to circle the tower a few times to have the opportunity to hit it.