In this building, you will find Intelligence missions you can complete. These consist of rescuing Survivors, hunting beasts, or having your Heroes battle their way through an investigation of a building.
You can upgrade the Searchlight by completing the required amount of missions shown at the bottom left of the screen. It will upgrade to a maximum of level 20.
Upgrading the Searchlight allows for more missions to be found during refreshes along with better quality missions. Better quality missions reward you with better prizes. Once you have completed all the missions available, you will need to wait until the reset to do more.
Always make sure to complete these as much as you can. The prizes are more than worth it.