An autopsy has been completed on murdered B.C. teen Taylor Van Diest, but Mounties aren't saying anything about how she was killed on Halloween night.

The 18-year-old died in hospital Monday after she was found unconscious and severely injured near the railroad tracks that run through the small Okanagan town of Armstrong.

At an RCMP press conference Friday, spokesman Gord Molendyk said that police are holding back the results of an autopsy completed a day earlier because they don't want to compromise the investigation.

He did, however, release more details of Van Diest's movements on the night she was killed.

Investigators now believe that the slain teen was last heard from at 6 p.m., 10 minutes after she left her family home to meet up with someone. She was dressed in a zombie costume at the time.

Friends say the last word from Van Diest was a text message to her boyfriend reading, "I'm being creeped."

Molendyk told reporters that her phone was found along the train tracks at 7:30 p.m., a little more than an hour she was was discovered lying gravely injured in a bushy area about 10 feet from the railway line.

Van Diest's family says that her boyfriend, Colton Luttmerding, was the one to make the gruesome discovery, but his mother says he is not ready to speak to the media.

In an attempt to solicit more tips in the murder, RCMP set up a roadblock Thursday evening near the place where Van Diest was found. Officers showed drivers Van Diest's picture, and asked if they had seen anything unusual on Halloween.

A suspect has yet to be identified, but more than 40 officers are working on the investigation.

With files from CTV British Columbia's Kent Molgat