Another Survivor

The PGR says that beyond the Ecuadorian who walked 20 kilometers with a bullet wound in his mouth, there is another survivor of last week's immigrant massacre, who has provided important info and has been in contact with authorities in his country. With two survivors and 72 dead, the total number of migrants at the time of the killing would seem to be 74. However, the Ecuadorian claims there were 76. So, is his memory faulty (which would be understandable), or there still two more survivors out there?