It was never explained. I’m guessing they called an ambulance and the police after leaving. They probably reported seeing a guy break into someone’s house.
If I recall, wasn't she conscious when the two were in the house? And if so, how would it have been explained that two people helped her and then all three disappear?
Just a plot point that could have been cleared up with some better writing...like a newscast that goes, "a woman was found in her home by relatives barely alive and tied up....she never saw the suspect's face"....
I would assume they untied her before leaving with her assailant. We can only speculate about what, if anything, she reported. I don't think anything in the narrative depends on it.
The victim was unconscious when the kids arrived, they untied her and pulled the bag off her head so she could breathe. Presumably she regained consciousness after they all left, and it would remain an unsolved crime.