Three days after an FBI agent was cleared of wrongdoing in the bizarre killing of an associate of slain Boston bombing suspect Tamerlan Tsarnaev, lawyers for Dzhokhar Tsarnaev, the only surviving bombing suspect, alleged that the FBI attempted to recruit the elder Tsarnaev as an informant. Dzhokhar Tsarnaev's defense team said that new information suggests the FBI interviewed Tamerlan on several occasions before the attack, and even pressured him to surreptitiously report on the Chechen underworld. The Bureau has continued to emphatically state that it didn't know the identities of the two suspected bombers until they were fingerprinted, and have denied any involvement with the brothers aside from following up on a tip from a Russian emissary that the elder Tsarnaev may have been seeking jihad. In the case of Ibragim Todashev, who allegedly took part with Tamerlan in a robbery turned triple-homicide in Waltham, in 2011, family members have also stated that FBI pressure may have pushed the 20-something ethnic Chechen and mixed martial arts fighter to the brink of violence. Since the terrorist attacks of 9/11, the Bureau has stepped up surveillance of specific racial, ethnic and religious communities, including the use of informants. The tactics have ... left the Bureau open to charges of entrapment, not to mention assorted Internet conspiracy theories. Part of those post-9/11 tactics are the use of voluntary interviews often encouraging interviewees to serve as informants in their communities," writes the American Civil Liberties Union.