1 [intransitive, transitive] to carefully examine the facts of a situation, an event, a crime, etc. to find out the truth about it or how it happenedThe FBI has been called in to investigate.(informal)“What was that noise?” “I'll go and investigate.” investigate somethingPolice are investigating possible links between the murders. investigate what, how, etc.…Police are investigating what happened.2 [transitive] investigate someone (for something) to try to find out information about someone's character, activities, etc.This is not the first time he has been investigated by the police for fraud.3 [transitive, intransitive] to find out information and facts about a subject or problem by study or research investigate (something)Scientists are investigating the effects of diet on fighting cancer. investigate how, what, etc.…The research investigates how foreign speakers gain fluency.Usage note: Crimecommitting a crimecommit a crime/a murder/a violent assault/a brutal killing/an armed robbery/fraud/perjurybe involved in terrorism/a suspected arson attack/human smuggling/human traffickingengage/participate in criminal activity/illegal practices/acts of mindless vandalismsteal someone's wallet/purse/watch/cell phonerob a bank/a person/a touristbreak into/burglarize a house/a home/an apartment/an officehijack a plane/ship/bussmuggle drugs/weapons/arms/people/immigrantslaunder (drug) money (through something)forge documents/certificates/passportstake/accept/pay someone/offer (someone) a briberun a phishing scam/an e-mail scam/an Internet scamfighting crimecombat/fight crime/terrorism/drug trafficking/corruptionprevent/stop credit-card fraud/child abuse/software piracydeter/stop criminals/burglars/thieves/shoplifters/vandalsreduce/tackle/crack down on gun/violent/street/property crimefoil a bank robbery/a terrorist plothelp/support/protect the victims of crimeinvestigating crimereport a crime/a theft/a rape/an attack/an incident to the policewitness a crime/an attack/a murder/an incidentinvestigate a murder/a homicide/a burglary/a robbery/the alleged incidentconduct/launch/pursue/open an investigation (into…)investigate/reopen a criminal/murder caseexamine/investigate/find fingerprints at the crime scene/the scene of crimecollect/gather forensic evidence/physical evidenceuncover/discover new evidence/a fraud/a scam/a plot/a conspiracy/political corruption/a cache of weaponsdescribe/identify a suspect/the culprit/the perpetrator/the assailant/the attackerquestion/interrogate a suspect/witnesssolve/crack the case⇨ more collocations at justiceUsage note: investigateinvestigate verbempirically, experimentally|theoretically|rigorously, systematically, thoroughly|extensively, furtherThis theory has been investigated experimentally by heating volcanic rock.This speculation needs to be investigated further.influence, interaction, relationship, role|effect, efficacy|hypothesisOur study aims to investigate the role of optimism in preventing illness.To investigate our hypothesis, we will present two analyses.investigation nounempirical, scientific|thorough|further, ongoingProposals for scientific investigations will probably increase as new discoveries are made.A thorough investigation of the evidence confirms this conclusion.conduct, undertakeWe conducted a follow-up investigation to determine whether or not the students enrolled in French the following year.demonstrate, reveal, show, uncover, yieldInvestigations showed no chemical contamination of the air or water.Recent investigations have yielded new insight into sleep's role in memory and learning.