The story: in a fantasy iron age world, a T-Rex-like animal (actually more like the size of allosaurus) has emerged from the forest and started killing people. The animal always retreats to the forest after making a kill, and it never strikes in the same place twice, which makes hunting it difficult. Because it's considered too dangerous to kill it head-on, a group of forest rangers decides to create a trap to kill it. The trap has to be placed deep in the forest to catch the animal off-guard, because it becomes very careful as it gets close to human settlements. The trap also has to leave as little trace as possible (scent or otherwise) so that the animal isn't deterred from approaching the trap. What kind of trap or approach would work best in this situation?
Aside from the traits described above, the animal has the characteristics of a tiger: it's solitary, would take its prey to the forest to eat later, somewhat good at climbing trees (the forest has really big trees), and is very sneaky. It usually lives in deep forests with heavy vegetation and eats forest animals as large as itself, but this one for some reason have a taste for people. It's as intelligent as a chimpanzee, can remember human faces, and can recognize that some humans are more dangerous than others (it's a point in the story that a character tries to kill it head-on but fails, and then the animal persistently chases him because it recognizes him as a threat, but also recognizes that he has lost his weapons and is currently helpless).
I realize that the obvious answer might be "use a trap for tigers but bigger", so please explain about the details and obstacles of using such trap so I can better incorporate it into the story.