Investigation | USAO | Department of Justice

Homeland Security Investigation (DHS/HSI). The investigators at these agencies investigate the crime and obtain evidence, and help prosecutors understand the ... Skiptomaincontent USAOSecondaryHeader YouarehereU.S.Attorneys»Justice101 Investigation Investigation IntheFederalGovernment,thereareagenciesthatemploycriminalinvestigatorstocollectandprovideinformationtotheUnitedStatesAttorneysintherespectivedistrict. Youmayalreadyknowsomeoftheagencies,suchas: FederalBureauofInvestigation(FBI) DrugEnforcementAdministration(DEA) BureauofAlcohol,Tobacco,FirearmsandExplosives(ATF) UnitedStatesSecretService(USSS) HomelandSecurityInvestigation(DHS/HSI) Theinvestigatorsattheseagenciesinvestigatethecrimeandobtainevidence,andhelpprosecutorsunderstandthedetailsofthecase.Theprosecutormayworkwithjustoneagencybut,manytimes,severalinvestigatingagenciesareinvolved. Partoftheinvestigationmayinvolveasearchwarrant.TheFourthAmendmentoftheConstitutionusuallyrequiresthatpoliceofficershaveprobablecausebeforetheysearchaperson’shome,theirclothing,car,orotherproperty.Searchesusuallyrequireasearchwarrant,issuedbya“neutralanddetached”judge.Arrestsalsorequireprobablecauseandoftenoccurafterpolicehavegottenanarrestwarrantfromajudge. Dependingonthespecificfactsofthecase,thefirststepmayactuallybeanarrest.Ifpolicehaveprobablecausetoarrestasuspect(asisthecaseiftheyactuallywitnessedthesuspectcommitacrime),theywillgoaheadandmakeanarrest. DirectEvidence Aprosecutorevaluatesacase,andusesallthestatementsandinformationtheyhave todetermineifthegovernmentshouldpresentthecasetotheFederalGrandJury—oneinwhichallthefactsleadtoaspecificpersonorpersonswhocommittedthecrime.However,beforetheprosecutormadethatconclusion,theyhavetolookatbothdirectandcircumstantialevidence.Directevidenceisevidencethatsupportsafactwithoutaninference.Testimonyofaneyewitnesstoacrimewouldbeconsidereddirectevidencebecausethepersonactuallysawthecrime.Testimonyrelatedtosomethingthathappenedbeforeorafterthecrimewouldbeconsideredcircumstantial. CircumstantialEvidence Thesecondtypeofevidenceiscircumstantialevidence—statement(s)orinformationobtainedindirectlyornotbasedonfirst-handexperiencebyaperson.Circumstantialevidenceincludespeople’simpressionsaboutaneventthathappenedwhichtheydidn’tsee.Forexample,ifyouwenttobedatnightandtherewasnosnowonthegroundbutyouawoketosnow,whileyoudidn’tactuallyseeitsnowing,youassumethatitsnowedwhileyouslept. LEGALTERMSGLOSSARY CRIMINALJUSTICESTEPS Investigation Charging InitialHearing/Arraignment Discovery PleaBargaining PreliminaryHearing Pre-TrialMotions Trial Post-TrialMotions Sentencing Appeal COURTROOMIMAGES FEDERALCOURTSYSTEM FAQ Wasthispagehelpful? Wasthispagehelpful? Yes No Thankyouforyourinput. ContacttheWebmastertosubmitcomments.