Dokka Umarov denies he has quit as head of Chechnya's armed separatist group.
The suspects are brothers. The at-large suspect is identified as a Kyrgyzstan-born Cambridge resident, 19-year-old Dzhokhar Tsarnaev. The deceased brother is identified as 26-year-old Tamerlan Tsarnaev. A number of YouTube videos, posted by the suspects, surface that seek Muslim takeover of Chechnya.
A Chechen man is sentenced to 12 years in prison after being convicted of trying to send a letter bomb to the Danish newspaper Jyllands-Posten, which had published drawings of the Muslim prophet Muhammad.