Transcript for Possible American Terror Recruits
Now, to another developing headline at this hour. Tonight, the FBI is investigating three American teenagers, high school students from Denver, who had left this country, lured away through the internet, they say. The teens were on the way to join terror groups in Syria. Take a look at the map tonight. They traveled all the way from Denver to Germany, more than 8,000 miles and that's where they were detained. ABC's senior justice correspondent Pierre Thomas tonight with who these teens are and he begins with the internet message those teens might have heard and listened to. Advice that I have for the sisters. Reporter: Sources tell ABC news slick video pro mows like this, preaching the virtue of jihad, were key to convincing three Denver teenage girls to leave their families behind. The teenagers of sew mall little and Sudanese decent, were only 15 and 16 years old. Seduced into flying for frankfu Frankfurt, Germany. It's very important they come to this place here. Reporter: But after they disappeared last weekend and their families became worried, the FBI was contacted and the girls were stopped and sent home. ABC news has learned Syrian radicals are specifically targeting women and girls to become their wives or fighters. We have houses. We have security. Reporter: This female recruit from Scotland is posting messages on Twitter, asking for support. If you cannot make it to the battlefield, then bring the battlefield to yourself. Tonight, U.S. Law enforcement officials are wrestling with these critical questions. Are these teens misguided children who have been victimized or potential terrorists who need to be prosecuted? David? Pierre Thomas live in Washington. Pierre, thank you.
This transcript has been automatically generated and may not be 100% accurate.