Do you believe the FBI holds the biggest number of bitcoin?
How would we know? How certain are they? We can't tell because nobody/no one would say how many bitcoins he/she has on his/her hands

Was it because the FBI news had managed to capture Medvedev a few days so that the FBI is said to be the largest bitcoin holder? I do not think so. Because there are still many out there people who hold more bitcoin than the bitcoin confiscated FBI. The bitcoin confiscated by the FBI is not his but the bitcoin belongs to the people who have been tricked by Medvedev so the FBI should return the bitcoin to those who have been deceived by Medvedev.