A Brussels apartment was likely a hideout for one of the Paris attackers, as well as a bomb-making shelter.
According to The Washington Post, Belgian police found the fingerprint of Salah Abdeslam, the brother of one of the attackers, during a raid of an apartment in Brussels' Schaerbeek district on December 10.
Abdeslam, 26, is believed to have participated in the November 13 attacks that killed 130 people. He is currently at large.
Also, the Brussels apartment contained three belts possibly used to carry explosives and traces of the same kind of explosives used in the attacks.
Abdeslam reportedly called two people to pick him up as the Paris attacks were taking place and was then taken to the apartment.
He and his friends were stopped by a French gendarme near the border but let go, the New York Post reports.
Belgian federal prosecutor Eric Van der Sypt reportedly said authorities "lost trace" of Abdeslam sometime afterward.
The two people who picked Abdeslam up during the attacks were since arrested.
Belgian police additionally arrested someone who possibly rented the apartment under a false name.