Sixteen-year-old Karlie Gusé vanished from her home in a rural California desert community on the morning of October 13, 2018.

TELL DR. PHIL YOUR STORY: Have a story in the news?

According to Karlie’s father, Zac, and stepmother, Melissa, the teenager had reportedly been acting “very strange” the night before her disappearance. Melissa says Karlie admitted to smoking marijuana, but she and Zac suspect it may have been laced with another substance.

WATCH ‘I Wholeheartedly Believe That Karlie Is Alive,’ Says Dad Of Missing Teen

Melissa says she stayed up with Karlie most of the night, before falling asleep around 5:45 a.m. When she woke up at 7:15, Karlie was gone.

Karlie’s mother, Lindsay, is alleging that Zac and Melissa know more than they’ve disclosed about the teenager’s disappearance. She says her suspicions didn’t arise until after she heard an audio recording that they had made of the teen the night before she vanished.

WATCH Dr. Phil On What Audio Of Teenager Recorded In The Hours Before Her Disappearance Could Reveal

Lindsay claims that on the recording the teen seemed both confused and concerned about her health. “You can hear her asking, ‘are you going to call 9-1-1?’” she claims

Continuing, she says, “It is very unsettling, knowing that they refused to call for help when she asked them to.”

Zac and Melissa say they don’t know where Karlie is. Melissa says she recorded Karlie because she wanted the teen to hear what she sounded like on drugs. She adamantly denies that the teen asked her to call 9-1-1.

When Dr. Phil listens to the recording, what does he hear?

Check here to find out where you can watch the conclusion of this two-part episode airing Tuesday.

Karlie Gusé is 5-feet-7 inches tall, 110 pounds, with brown hair and blue eyes. If you have any information about the disappearance of Karlie, please call the Mono County Sheriff at 760-932-7549. Choose option #7.

TELL DR. PHIL YOUR STORY: Is Dr. Phil your only hope?

What Karlie Gusé’s Mother Says About The Day She Learned Her Daughter Went Missing