Corrected on January 26, 2015
An earlier version of this post said authorities were trying to determine where the gun that killed Nisman came from. An associate of Nisman has said he gave him the gun.
The earlier version also said testimony by a locksmith that the deceased's door was unlocked undermined the theory of suicide. The testimony was later disputed by the dead man's mother who has said she partially unlocked the door before the locksmith arrived.