public sealed class KnowledgeGraphInvestigationProjectItem : KnowledgeGraphBaseProjectItem, ArcGIS.Desktop.Core.IMetadata, ArcGIS.Desktop.Core.IProjectItem, ArcGIS.Desktop.Mapping.IMappableItem, System.ComponentModel.INotifyPropertyChanged  

{
  // open an existing investigation
  var investigationProjectItems = Project.Current.GetItems<KnowledgeGraphInvestigationProjectItem>();
  var investigationProjectItem = investigationProjectItems.FirstOrDefault(ipi => ipi.Name.Equals("myInvestigation"));
  await QueuedTask.Run(() =>
  {
    KnowledgeGraphInvestigation investigation = investigationProjectItem.GetInvestigation();
    ProApp.Panes.CreateInvestigationPaneAsync(investigation);


    // or 
    investigation.OpenViewAsync();
  });

  // or 
  investigationProjectItem.OpenInvestigationPaneAsync();
}

{
  var containerPath = "KnowledgeGraph";

  // find the first container with the correct path (key)
  var invContainer =
     Project.Current.ProjectItemContainers.FirstOrDefault(c => c.Path == containerPath);

}

{
  var investigationContainer = Project.Current.GetProjectItemContainer("KnowledgeGraph");
  var item = Project.Current.GetItems<KnowledgeGraphInvestigationProjectItem>().FirstOrDefault();

  //Select the fc
  if (item != null)
  {
    var projectWindow = Project.GetCatalogPane();
    await projectWindow.SelectItemAsync(item, true, true, investigationContainer);
  }
}

{
  // open an existing investigation
  var investigationProjectItems = Project.Current.GetItems<KnowledgeGraphInvestigationProjectItem>();
  var investigationProjectItem = investigationProjectItems.FirstOrDefault(ipi => ipi.Name.Equals("myInvestigation"));
  await QueuedTask.Run(() =>
  {
    KnowledgeGraphInvestigation investigation = investigationProjectItem.GetInvestigation();
    var panes = investigation.GetInvestigationPanes();

    foreach (var pane in panes)
    {
      KnowledgeGraphInvestigationView kgView = pane.InvestigationView;
      // if it's the active investigation view
      if (kgView == KnowledgeGraphInvestigationView.Active)
      {
        // do something
      }
    }
  });
}

{
  // get an existing investigation
  var investigationProjectItems = Project.Current.GetItems<KnowledgeGraphInvestigationProjectItem>();
  var investigationProjectItem = investigationProjectItems.FirstOrDefault(ipi => ipi.Name.Equals("myInvestigation"));
  await QueuedTask.Run(() =>
  {
    // get the datasore
    using (var kg = investigationProjectItem.GetDatastore())
    {
      // do something
    }
  });
}

{
  //Confirm if investigation exists as a project item
  KnowledgeGraphInvestigationProjectItem investigationItem =
     Project.Current.GetItems<KnowledgeGraphInvestigationProjectItem>().FirstOrDefault(
                                                        item => item.Name.Equals("myInvestigation"));
  if (investigationItem != null)
  {
    KnowledgeGraphInvestigation investigation =
       await QueuedTask.Run(() => investigationItem.GetInvestigation());

    // see if a view is already open that references the same investigation
    foreach (var investigationPane in ProApp.Panes.OfType<IKnowledgeGraphInvestigationPane>())
    {
      //if there is a match, activate the view
      if (investigationPane.InvestigationView.Investigation == investigation)
      {
        (investigationPane as Pane).Activate();
        return;
      }
    }
  }
}