I'm thinking that the unsung hero in this film (figuratively speaking) is Mr. Galloway, the would-be child killer. Hear me out! By that, I mean, he stole the show imo. He considered himself bound to this women's behest, and was given a mission from Hell. I was very intrigued by his character and connection to the main couple.
I will say I found this film misleading in that the summary implied the child's mother was the target. I still found the film psychologically gripping. Give it up for my home gal Jennifer Lawrence who plays an amazing nutjob.
The symbolism of the panther getting him in the end was very morally satisfying. I would recommend the movie to others looking for a good thriller. (Would say it's not Bradley Cooper's best role by a long shot.)