From Longman Dictionary of Contemporary Englishinvestigationin‧ves‧ti‧ga‧tion /ɪnˌvestɪˈɡeɪʃən/ ●●● W2 AWL noun 1 [countable]SCCSCP an official attempt to find out the truth about or the cause of something such as a crime, accident, or scientific problem The investigation continued for nearly three years.investigation into The authorities are planning to launch a full-scale investigation into the crash.investigation of Baker demanded an investigation of the district attorney’s office. a criminal investigation A private detective was hired to conduct the investigation.2 [uncountable]INVESTIGATE the act of investigating somethinginvestigation of the investigation of computer fraudunder investigation (=being investigated) The whole issue is still under investigation.THESAURUSinvestigation a process in which the police or another organization try to find out the truth about a crime or accidentFollowing a major police investigation, two men were arrested.The investigation into the causes of the air crash are continuing.inquiry an official process to find out why something happened, which usually takes several months or yearsLocal people are calling for an inquiry into the accident.An independent inquiry found serious shortcomings at the children’s home.case a matter that police or officials are trying to find out information about, especially so that it can be dealt with in a court of lawThe case has never been solved. The police say it is one of the most puzzling cases they have had to deal with.probe an investigation in which many questions are asked to find out the truth about something – used especially in journalismThe TV show featured a probe into charges charged by high street banks. inquest a legal investigation to find out why someone diedThe inquest heard that Mr Swan was poisoned.survey a process in which people are asked questions in order to find out about their opinions or about their behaviourThey did a survey to find out the most popular pop star. Based on a survey of 250 companies, the report says that ‘ over two thirds of companies expect operating costs to increase as a result of addressing environmental issues.autopsy British English a medical examination of a dead person’s body, to find out why that person diedIf she died of a drug overdose, it would show up in the autopsy.
Examples from the Corpusinvestigation• a criminal investigation• Prison officials are carrying out a full investigation after two prisoners escaped from a prison vehicle.• Following a major police investigation, two men have been arrested.• The investigation into the cause of the air crash is continuing.• the investigation of drug smuggling• The Senator promised a thorough investigation into the fund-raising activities of both parties.conduct ... investigation• Bill Thomas, R-Calif., shortly before the House voted 224-187 to authorize an eight-member panel to conduct the investigation.under investigation• Dodd is still under investigation.