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Fact Sheet

Just What Is An FBI Investigation? A Fact Sheet

In the aftermath of the bombing at the Boston marathon, there have been a host of reports about the FBI’s investigation of the two suspects. This fact sheet explains different categories and features of several different types of FBI investigations.

Published: May 20, 2013

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In the after­math of the bomb­ing at the Boston mara­thon, there have been a host of reports about the FBI’s invest­ig­a­tion of the two suspects, Dzhokhar and Tamer­lan Tsarnaev. When it was revealed the Bureau had inter­viewed Tamer­lan Tsarnaev in 2011 after Russian intel­li­gence had warned he might hold “extrem­ist” views, ques­tions arose anew about the Bureau’s sleuth­ing abil­ity.              

The FBI conducts several differ­ent types of invest­ig­a­tions, and each is governed by certain rules, as set out in guidelines issued by the U.S. Attor­ney General. These guidelines have been modi­fied over the last decade to give the FBI broad latit­ude and author­ity in conduct­ing invest­ig­a­tions.

Even at the assess­ment stage, where the FBI can initi­ate an invest­ig­a­tion without any indic­a­tion of terror­ist or crim­inal activ­ity, it can gather a wide range of inform­a­tion. As evid­ence of a possible national secur­ity threat or crime accu­mu­lates, the FBI can use more and more intrus­ive invest­ig­at­ive tools. The FBI does not have to start with an assess­ment and work its way up; if it has suffi­cient inform­a­tion, it can start at the top.

Below is an explan­a­tion of the categor­ies and some of the features of FBI invest­ig­a­tions.

Features of FBI Invest­ig­a­tions
  What’s Required? Who Can Do It and For How Long? What Can They Do?
Assess­ment Basic­ally noth­ing. Just an “author­ized purpose” and a “clearly defined object­ive.” No “prob­able cause” or “reas­on­able suspi­cion” is required. Any FBI agent can conduct an assess­ment for 30 days without super­vis­ory approval. After that, the agent must report to a super­visor, and the invest­ig­a­tion can be renewed every 30 days. There is no expli­cit time limit, though the dura­tion is expec­ted to be “relat­ively short.” Among other things, recruit inform­ants to monitor the subject, ques­tion people without reveal­ing the agent’s iden­tity, search commer­cial and govern­ment data­bases, and conduct phys­ical surveil­lance of a person’s public move­ments.
Foreign Agency Request A request from a non-U.S. law enforce­ment, secur­ity or intel­li­gence agency. Any FBI agent and there is no time limit. Everything that is allowed in an assess­ment. If an invest­ig­ator wants to go beyond these meth­ods, a super­visor’s approval is required.
Prelim­in­ary Invest­ig­a­tion “Inform­a­tion or an alleg­a­tion” about a national secur­ity threat or possible crim­inal activ­ity. Any FBI agent for six months, with super­vis­ory approval. The invest­ig­a­tion can be renewed for another six months by the agent-in-charge. FBI offi­cials in Wash­ing­ton, D.C. must author­ize addi­tional exten­sions. All the tech­niques used in an assess­ment, plus tracing phone numbers of all incom­ing and outgo­ing calls, acquir­ing records of Inter­net activ­ity, obtain­ing records held by banks, phone compan­ies and Inter­net service providers, and eaves­drop­ping on private conver­sa­tions from a public space through the use of high-powered micro­phones. Depend­ing on the circum­stances, prior approval by FBI managers may be required for some of these tech­niques.
Full Invest­ig­a­tion An “artic­ul­able factual basis” of a possible national secur­ity threat or crim­inal activ­ity. Any FBI agent (likely a team) with super­vis­ory approval. No time limit. Everything listed below, plus judi­cially-approved actions such as wiretaps, open­ing mail, monit­or­ing and inter­cept­ing email, covert searches of homes and offices, and attach­ing devices to cars to track travel.