A Detroit teenager who forced his ex-girlfriend to watch as he hacked her mother and new boyfriend to death was reportedly obsessed with the movie "American Psycho" and left a series of disturbing messages on his Facebook account in the weeks before the attack.

Police say 19-year-old Brian Douglas White entered the home of his ex-girlfriend early Wednesday and went on a killing rampage, using an ax to kill the girl's mother, Angela Kim Staperfene, and her current boyfriend, 19-year-old Jacob Lee Burns, while they slept. White then shot himself to death.

The 17-year-old girl, a senior at Stevenson High School whose name hasn't been released, was injured in the attack inside her Livonia, Mich., home but managed to escape and call 911. Livonia, a city of 100,000, is about 15 miles west of Detroit.

A string of messages reportedly posted by White on his Facebook page in the weeks before the rampage reveal a deeply troubled teenager. 

"You can get addicted to a certain kind of sadness," White wrote on his Facebook page, which has since been taken down, the Detroit News reported. 

"What a polite murderer," he wrote on March 27, according to the newspaper. 

Another posting from March 29 reportedly read: "And with a sad heart I say bye to you and wave, kicking shadows on the street for every mistake that I had made."

The family of 19-year-old Burns expressed their grief over his death, telling Fox affiliate WJBK-TV that he was a standout athlete who "put a smile on everybody's face."

"Everybody he met was a friend," his father, Robert Burns, told the station.

"I don't think we'll ever know what was going on inside that young man's head," he said of his son's killer. "For whatever purpose that this happened, I have no clue. I don't think we'll ever know."

Friends of the 17-year-old girl described her as an aspiring model who was outgoing and compassionate. A neighbor told the Detroit News that the girl had rejected White earlier this week when he confronted her at school.

"He was very controlling," neighbor Lisa Collins told the newspaper. "That's why she broke it off with him."

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Livonia Double Murder-Suicide Victim Jacob Burns' Father: 'No Clue' Why This Happened: MyFoxDETROIT.com