A middle school student in Incheon was apprehended Thursday for allegedly killing a mentally disabled girl after a failed rape attempt.

Police said the 16-year-old suspect tried to rape the 12-year-old victim at a building after kidnapping her on her way home from school Wednesday.

After failing to rape her, he lured her to a nearby field by asking her to play.

He reportedly made a hole in the field with a small shovel he had brought with him, made her lie in the pit, and suffocated her to death by covering her face with a bag.

He told police that he killed her “because she spoke impolitely while playing.”

“The suspect suffered from manic disorder and emotional disturbance which often lead to aggressive behavior,” a detective chief in charge of the case said.

They were in the same class for mentally and physically disabled students in elementary school years before.

The police received a report from the victim’s parents on Wednesday night and proceeded with the investigation by analyzing closed-circuit television footage near her school.

By Kim Young-won (wone0102@heraldcorp.com)