"To complete the investigation" means to finish the process of gathering information and examining evidence in order to find out the truth or solve a problem. Full definition
They must complete their investigation into whether this disputed entry should remain on your report within that same 30 - day period. (badcredit.org)
The bureaus have 30 days to complete an investigation of your dispute and provide written documentation of their findings. (legacylegal.com)
You leave on an expedition any time you leave the city through one of the gates or when you wander off after completing an investigation quest. (polygon.com)