He was hunting for a victim, he is a predator. He wasn't trying to talk to her. He stalked her, chased her down, kidnapped her and murdered her. It had NOTHING to do with him being mad, scared or whatever because she was going to call the police. He intended to do exactly what he did. He is a low life criminal who thought that he could kill her, rape her (likely) dump her in a corn field and no one would try too hard to find out who did it - like back home in his country where women are not valued.
There are probably other victims but they may also be illegally in the country and are therefore not missed or didn't report what he has done. I don't for one minute believe that he committed his first crime at age 24 and it was was kidnapping and murder. He's been preying on people his whole life. Bet on it.
Predators are born predators and are always on the prowl for victims.