(ANCHORAGE, Alaska) — An Alaska teenager allegedly killed her “best friend” after a man she met online offered to give her millions if she showed evidence of the murder, authorities said.Investigators said Denali Brehmer, 18, launched a plot to murder her 19-year-old friend, Cynthia Hoffman, last month after a man promised her $9 million or more to “rape and murder someone in Alaska” and send him “videos and photographs of the murder,” prosecutors said in an indictment. The indictment, obtained by ABC News on Tuesday, claimed Darin Schilmiller, 21, of Indiana, used another man’s photo for several months online, pretending to be a millionaire named “Tyler” from Kansas.”Brehmer agreed to commit a murder for him,” the indictment stated. “Digital evidence and statements show Brehmer was communicating with and sending videos and/or photographs of the events surrounding the incident to Schilmiller at his directive throughout the duration of the event.”Authorities said they found Hoffman’s duct tape-bound body in a river near a rural Anchorage hiking trail on June 2. Police said she died of a gunshot wound to the back of the head, but there was no evidence to show that she was sexually assaulted.Brehmer was charged with first-degree murder in the online “catfishing” case, although police said 16-year-old Kayden McIntosh pulled the trigger and 19-year-old Caleb Leyland provided the vehicle to carry out the plot, the indictment stated.Police said McIntosh, along with Brehmer, attempted to cover up the death by destroying the victim’s clothing, cellphone and purse. Brehmer allegedly texted the young woman’s family after she was dead, saying she’d been dropped at a local park.The suspects admitted their roles in the crime to police and said they were planning to split the money Brehmer received from Schilmiller, who eventually confessed to the scheme, according to the indictment.Police said Schilmiller also admitted to targeting Hoffman. He said the two also discussed murdering a second person, but they abandoned the plan.”[Schilmiller] told police that he knew Hoffman was best friends with Brehmer. He further admitted to telling Brehmer to kill Hoffman and that he and Brehmer had been planning a murder for three weeks,” the document stated. “Schilmiller further admitted to attempting to blackmail Brehmer after the homicide into raping people.”A grand jury indicted the six suspects — Brehmer, McIntosh, Schilmiller, Leyland and two unidentified juveniles — on charges of first-degree murder, first-degree conspiracy to commit murder and two counts of second-degree murder and other charges.Prosecutors said Schilmiller is currently in federal custody in Indiana on child pornography charges.In a press conference Tuesday, Bryan Schroder, U.S. attorney for the state of Alaska, announced Schilmiller and Brehmer have also been indicted by a grand jury on federal child pornography charges. The duo is now facing charges of conspiracy to produce child porn, production of child porn, receipt and distribution of child porn and coercion and enticement of a minor.Brehmer allegedly sexually abused a 15-year-old girl at Schilmiller’s urging, the evidence of which the FBI says it found on Brehmer’s phone.”For all the good the internet can do, it can be a very dark place and parents would be wise to monitor the activity of their children online,” Schroder said Tuesday. Copyright © 2019, ABC Radio. All rights reserved.