CONWAY, N.H. (MyFoxBoston.com) -- Nearly one month after the disappearance of a New Hampshire girl in the Conway-area, there is still no sign of her.
Abigail Hernandez vanished after leaving Kennett High School. Investigators have intensely searched the Conway area, but haven't found any sign of the 15-year-old.
FOX 25's Bob Ward talked to the ranking FBI agent working the Hernandez case, Kieran Ramsey. Ramsey said there was no firm indication what happened to the teen.
"We searched the greater Conway area by both air and land as well as on the water. We found nothing, sadly," said Ramsey.
The timeline of her disappearance begins at 2:30 p.m. on Oct. 9. Abby leaves Kennett High School, walks along Eagles Way and takes a short cut through a power line trail. Ramsey said the FBI confirmed two classmates who know Abby saw her going toward the power line trail.
From there, she was never seen again, but for a full 20 minutes she is using her cell phone to text a friend.
"Between 2:23 and 2:53 is where the last known text message she sends to that specific classmate is made," Ramsey said.
He said there was nothing unusual about the text messages and no other students had any communication with her.
"Fairly innocuous, nothing that's caused us concern," said Ramsey. "That individual has been very cooperative with us in the investigation."
After the texting stops, Abby's cell phone continues pinging a cell phone tower on Cranmore Mountain until 3:07 p.m.
"What causes a phone to no longer ping?" asks Ward.
"It could be turned off, it could be put in water or it could be destroyed," said Ramsey.
Ramsey said using the cell phone communications gave investigators a general area to search, but they were "all to no avail."
Authorities don't believe Abby ever made it home.
"This is a 14-, now 15-year-old girl that had a lively social media presence, that was very actively engaged in talking to her mom, classmates , and her friends and everything stops at 3:07 that afternoon," said Ramsey. To think she willingly left, on her own, and has stayed dark since then is an extensive commitment on the part of a 15-year-old girl."
"Is there any conclusion that we can reach that Abby is still alive at this point?" asks Ward.
"That's really hard to say. That's our greatest hope: that she is OK, that we can reunite her with her family," said Ramsey.
The FBI is also examining the cases of other missing people in the area. Most notably, the cause of Maura Murray – a UMass student who disappeared from Haverhill, N.H. nearly 10 years ago. Evidence from those cases has been sent to the FBI Behavioral Science Lab in Quantico, Virginia in an effort to find any patterns.
Meanwhile, a $20,000 reward has been offered in the case. Anyone with information that could help the FBI should dial 1-800-CALL-FBI.