расследования

In a sentence

• Полиция начала расследование преступления.

  The police began the investigation of the crime.

  Here, 'расследование' is used in the singular form to signify the activity or process of investigating a specific incident, emphasizing its formal and official nature.

• Её книга рассказывает о расследованиях журналиста.

  Her book tells about the investigations of a journalist.

  In this sentence, 'расследованиях' is used in the plural form and instrumental case to describe multiple investigative activities conducted by a journalist, stressing repeated or varied nature of these activities.

• Расследования показали, что причина аварии крылась в технической неисправности.

  The investigations revealed that the cause of the accident lay in a technical malfunction.

  Here, 'расследования' in plural form nominative case is used to indicate the results of multiple investigative actions regarding an incident, highlighting their outcome.