They are Chechen brothers, students, and the suspected masterminds behind the Boston Marathon bombings.
Tamerlan Tsarnaev, 26, is dead. Dzhokhar Tsarnaev, 19, is in police custody, but the details of their lives, particularly their ages and recent religious devotion, are prompting new concerns among experts.
Joan Neuhaus Schaan is the director of the Texas Security Forum.
"When you think of Houston and how many international students we have that come from regions that are involved in conflicts based on religion, any one of those students could end up being targeted by an extremist group and go through the same process," Schaan said. " We could find ourselves in that position here in Houston."
As interest in Chechnya's ties to terrorist groups and attacks grew Friday, Sean Thomas, an American journalist working for the Russia Today news program in Moscow chatted with our Fox 26 Newsroom.
"First of all, the most important thing is Chechnya is a part of Russia," Thomas said. "Think of it as a state. Chechnya is like Texas is to the United States, so Chechnya is to Russia. What you're seeing (over here) is Russians trying to distance themselves, and you can see why they would want to do that."
In Houston, Schaan continued her analysis.
"I thought what was interesting was the similarity between these to brothers and Faisal Shahzad, who is the Time Square bomber, Faisal Shahzad was completely under the radar before the Time Square bombing. He also used a pressure cooker. He was also a student. He had been naturalized as a citizen approximately a year before the attack."
Dzhokhar, the younger of the two brothers, became an American citizen on September 11, 2012. His alleged involvement in Boston surprised his family, friends and neighbors.
"I don't know if this is the new pattern that we really need to be concerned about. We are facing more and more threats that we had no idea of in advance," Schaan said. "Najibullah Zazi was the fellow from Denver who had a push cart business on wall street was also seemingly below the radar until the last minute."