them. now to boston. two weeks after the marathon bombings, investigators are still working to understand how the tsarnaev brothers were radicalized. over the weekend, we learned russian authorities briefed the u.s. officials in the days after the attack about a 2011 conversation between the older suspect, tamerlan tsarnaev, and his brother, in which they discussed jihad and a possible trip to palestinian territory. however, that information, which was captured through a wiretap, was apparently not shared with u.s. intelligence until after the april 15th bombings. counterterrorism officials have also confirmed the tsarnaev's mother was placed on the cia's counterterrorism database in the fall of 2011. that's the same time her eldest son, tamerlan, was put on the same list. now officials have continued their search for an unspecified number of person of interests.