The second survivor , who is from the United States , is now in El Salvador . Mexican president says his testimony could help authorities crack the case . Mexican investigators have not released information about a third survivor . Authorities are still identifying the remains of the about a third migrants killed .
The second survivor , who is from the United States , is now in El Salvador . Mexican president says his testimony could help authorities crack the case . Authorities are still identifying the remains of the about a third migrants killed .