LONDON -- Scotland Yard is heading the search for three London schoolgirls who disappeared last week, but Monday marks almost a week since they boarded a plane for Turkey, and as CBS News' Elizabeth Palmer reports, their families are clinging to a slim hope that they haven't yet crossed the border into Syria.
The family of the youngest girl, 15-year-old Shamima Begum, decided to go public over the weekend with an appeal they can only hope the girls will see.
Her older sister faced the cameras, holding Shamima's pink pyjamas.
"She didn't take anything with her. We are just clinging on to the bits that we have, and we just want her to come home," said Renu Begum. "If you watch this, baby, please come home. Mom needs you more than anything in the world. You're our baby and we just want you home, we want you safe."
The father of another 15-year-old Amira Abase echoed the plea.
"What she's doing is completely nonsense," he said. "Just remember how we love you, and your sister brother, they cannot stop crying."
The three teenagers, Shamina, Amira and Kadiza Sultana were all strong students at the same school in East London.
The last known picture of them was taken by a security camera at Istanbul airport last Tuesday.
They told their parents they were going out to study. Instead they boarded the plane from London's Gatwick Airport.
The trio was not stopped by the airline or U.K. border officials, and Palmer says there's now a lot of finger-pointing in Britain, but no clear answers.
Britain's Prime Minister David Cameron issued a warning for "every school, every university every college, every community to recognize they have a role to play, we all have a role to play, in stopping people from having their minds poisoned by this appalling death cult."
In online videos, the so-called death cult in question, the Islamic State of Iraq and Syria (ISIS) invites young women to join, offering them roles as nurses, cooks, wives and propagandists.
In fact, another teen, Aqsa Mahmood, who left her home in Britain to join ISIS last year, may have used social media accounts to encourage the most recent three girls to set out on their long and dangerous journey.
The recruitment message from ISIS, also known as ISIL, is slick, well-produced and effective. It targets impressionable Muslim teenagers in the West who often feel they don't quite fit in with the society around them. But for young women, it's not just the battle that beckons.
"Becoming wives of fighters seems to be a common thing; to take part in ISIL activities in that way, by marrying and producing children, jihadist children, or becoming part of the fight themselves," Steven Pomerantz, a former chief of counterterrorism at the FBI, told CBS News in October.
"We are concerned about the numbers of girls and young women who have or are intending to travel" to ISIS territory in Syria, London Metropolitan Police commander Richard Walton said on Friday.
As CBS News' Clarissa Ward reported in December, the girls who heed ISIS' call are often educated and from middle-class backgrounds. Rarely do their families know what is happening until it is too late. The phenomenon has been dubbed "bedroom jihad," and dozens of girls have been lured to one of the most dangerous war zones in the world as a result.
"The choice of returning home from Syria is often taken away" from young women and girls who travel to ISIS territory, said Walton, adding that if British authorities are able to find them while they're still in Turkey, "we have a good possibility of being able to bring them home to their families."