A US man used a fake Facebook account to lure a teenage girl out of her house in an attempt to stage her kidnapping and rescue so he could look like a hero, but ended up killing her, a police affidavit says.

Kyle Dube was indicted on Wednesday on charges of murder and kidnapping in the death of 15-year-old Nichole Cable, whose body was found in a wooded area in Maine this month a week after she went missing.

Killed: Nichole Cable.

In an affidavit released on Wednesday after Dube was indicted, Detective Thomas Pickering outlined the scenario leading to the high school sophomore's death. He wrote that Dube told his brother that he used Facebook to trick her into going out of her house while he waited in the woods wearing a ski mask.

When Nichole came along, the 20-year-old Dube jumped out and snatched her, duct-taped her and put her in the back of his father's pick-up truck, the affidavit said. Dube later discovered that she was dead, so he dumped her body and covered it with branches, it said.