Joni Shannon, Tammye Markle and Tina Wiley believe their friend, Lisa Stone, vanished on the first weekend of June 2010. On Saturday, June 5, Lisa's regular daily Facebook postings just stopped.
"I called her cell phone and it was disconnected," says Tina.
"I'm sick to my stomach, something's wrong," adds Tammye.
That very same day also appears to be the last day anyone physically saw Lisa Stone.
"It was the 5th that Lisa was over here," says neighbor Juanita Burris. It was also the last time she says she saw Lisa.
Juanita lives two doors down from Lisa, and says on that on Saturday, Lisa came calling just like clockwork.
"I think she depended on me for advice," she tells Maureen Maher. "She would come over here and sit in that chair...She was always around. She was in the yard or she was at your house or she was calling you. ...You could look out and you could see Lisa."
Juanita says a day didn't go by that that she didn't see Lisa.
The two women chatted that Saturday night and Lisa promised to return the next day to take out Juanita's garbage. Lisa never showed up.
"Sherry called me the next day, which was very unusual," she says. "She called me and she said Lisa's having a gallbladder attack and she said she's lying down. Then she said she could come over and take it out. And I said that'd be fine. And she never - she's been over here maybe one time."
"One time in how many years?" Maher asks.
"The whole time she was over there," Juanita replies.
Three days later, on June 9, there was another curious development: Joni got a hit on her Facebook page. "I knew it wasn't Lisa because of the way it was worded. It said, 'Joni, how are you and family?'" she says.
Lisa's Facebook page, which had been eerily dormant for three days, lit up again. But the ladies say they're sure it was not Lisa who sent the message.
She never talked to me like that," Joni explains. "She'd say, 'Tell Steve hi' or 'How is Steve?' She always said his name. Not 'how are you and family?'"
"What was your first reaction when you read it," Maher asks. "Were you at all relived?"
"No," Joni replies, "'cause I knew it was Sherry."
Sherry says she's never even been on Facebook.
"I don't know how to log on....I don't know anything about Facebook," she tells Maher.
Ten days later, Juanita Burris was worried enough to go to the Dallas police to file a missing persons report.
"Well, he said, 'Oh, she's probably just somewhere. She'll be back,'" Juanita says of the police reaction. "And I said, 'Something has happened to her.'"
Asked if she thought the police took her report seriously, Juanita says, "No. They thought I didn't know what I was talking about."
Within two days, on June 21, a detective did stop by Lisa's house. Sherry told the officer there was nothing to worry about. Lisa was simply away.
"They just accepted that as the truth and closed the file," says Tammye.
"We didn't feel like the police were responding," adds Tina.
The Facebook friends called Sherry repeatedly to ask where Lisa was.
"Everyday I was told a different story," Tina says. "Every day, Lisa was off here, Lisa was off there..."
For example, Sherry told the ladies that Lisa was working odd jobs for friend Pat James - helping her in the garden.
"I had hand surgery and I couldn't do a lot of work in the garden, so I hired her and she'd come over every morning around nine and she'd stay till about five," says Pat.
But that was in May, well before Lisa disappeared.
"I was in Florida three weeks and Lisa's friends, Tammye and Tina, they both called me in Florida - they had tracked me down, and I says, 'What's up?' 'Well, Lisa's disappeared.' And I said, 'disappeared?'"
Finally, on June 29, terrified that something truly awful had happened to Lisa, Joni and Tina confronted Sherry.
"Joni and I went there one night...Sherry let us in," Tina explains. "And we sat down and talked for an hour and a half."
"She said, 'Oh...Lisa's working, she's on her way home and I've ordered us a pizza,' and this was like 8 p.m.," Joni recalls.
"What did she tell you?" Maher asks the women.
"Nothing," says Tina
"Did you think Lisa was coming home?"
Eventually, the ladies just left. But Sherry says actually, they never showed up.
"Did any of her high school friends come over in June and say we want to see her? And you said according to them: "She's on her way home, I've ordered a pizza, you can come in and wait for her." Did that ever happen?" Maher asks Sherry.
"No," she replies.
"It never happened?"
"They're adamant that they came over to the house..."
"They can be as adamant as they want to."
Almost a month after Lisa was last seen, Joni says she decided to surprise Sherry and swing by Lisa's house again. And that led to an unbelievable chance encounter.
Joni sent Tina a text as she drove into Lisa's neighborhood.
"Joni said she was gonna go by the house and see if she came home with Lisa," Tina recalls, "so I was just about to type when Joni called me."
"'Tina... guess what? Sherry is driving Lisa's car and sitting beside me at a red light,'" Joni says of her call to Tina.
Asked if Sherry noticed her, Joni says, "No. And I panicked for a moment because I couldn't believe this. I was like, 'Oh my goodness.' I said, 'Oh my gosh... what do I do?' And she said, 'Follow her!'
"So I followed Sherry," she continues. "She pulled into a 7-Eleven parking lot... she pulls in front of the dumpster... I pull behind the gas pump and just get out of the car...and I'm hiding behind the pump, watching her and she proceeded to open up the trunk and started pulling out baskets and a little suitcase and proceeded to throw them into the trash dumpster."
In the dumpster, Joni says she found a suitcase full of Lisa's most personal belongings.
"...Lisa's birth certificate was in there. Her deceased brother Dennis - his death certificate was in there. Bibles," Joni says. "Just real precious personal things she would not have disposed of."
Why would Sherry dump Lisa's belongings? Sherry says she didn't.
"We'll here's what I'll tell you about the dumpster incident... There is no dumpster incident," says Sherry.
"When you say there was no dumpster incident, do you deny that you threw a blue suitcase full of personal items inside the dumpster?" Maher asks.
"You were never there?"
"It's all a flat out lie?"
"Flat out lie..."
The ladies had had it.
"I just thought that nothing she had told me had been true," says Tina.
Armed with evidence from the dumpster and a timeline of events, on July 3, the women marched into police headquarters and demanded action.
Joni says, "We met at the Dallas police downtown office...and walked in the front door and said, 'You're gonna listen to us.'"
The cops agreed to take another look. But that didn't mean the ladies were about to let go of their own investigation. They tapped into the power of Facebook, asking Lisa's Facebook friends for any information that might help them find her.
It worked. One of the strongest Facebook clues led them to a creek bed near Lisa's house - the same place where Sherry Henry was seen running and covered in mud.