A 25-year-old man allegedly ordered his ex-girlfriend into his car, took her cell phone, assaulted her and threatened to kill her Saturday night, police said.

The man later turned himself into police and was arrested for investigation of kidnapping, second-degree theft, first-degree terroristic threatening, second-degree assault and violation of a temporary restraining order.

The 22-year-old former girlfriend was riding in a car with a male friend in Wahiawa around 5 p.m. Saturday when the ex-boyfriend began following them while honking his horn, police said. The friend pulled over and the ex-boyfriend ordered the woman into his car, police said.

They drove around to several locations for more than an hour while the ex-boyfriend allegedly took the woman’s cell phone, assaulted her and threatened to kill her, police said. The ex-boyfriend then drove the woman home and let her go, police said.