Why is the sentence "so there was nothing to fear from them" (lines 73-74) ironic? What does it foreshadow?

The line is ironic for even after the family of Don Lupe had gone, either dead or the children taken away to far away lands, he still had to live a life in hiding, "like a leper", scared of any new stranger in town.

It foreshadows the event that will be upon him, being hunted and eventually tortured and killed by the son of the very man he had killed.

Explanation:

The short story "Tell Them Not To Kill Me" by Juan Rulfo is a story about an accused man on death penalty. The accused Juvencio Nava had murdered his neighbor Don Lupe over a mere trifling issue of their cattle grazing in the other person's land. And for this crime, he had been guarding himself from being detected, which after the death of the victim's wife and the young children taken to far away place to their relatives, he had thought himself safe from any retribution.

The line "so there was nothing to fear from them" is said by Juvencio while recounting the past years he had lived during the murder. He stated that with the death of Lupe's wife due to grief, and the children being taken to stay with relatives in a far away places, he has nothing to worry about anymore. He could easily live his life without the fear of being hunted.

But this speech is ironic for it actually happened in the opposite way. He had to live in hiding for many years, and would flee to the mountains whenever someone new came into town.

The line also foreshadows the future events where he will be captured and killed by the son of the murdered man. The colonel who had him captured has come to pass judgement on him. As it turns out, he was the son of Don Lupe, and had wanted to exact revenge on his father's killer. In the end, Guadalupe Terreros' son had avenge his father's murder.