In the proctoring screen, within both the exam monitor and the "Super Monitor", you can flag examinees (for example, those deemed suspicious) and add them to a watch list. 

See how this is done in the following demonstration. Click "Play Demo" to view it; you can also try it out yourself by flagging examinees and navigating to the "Watching" screen to monitor them. 

Note that at the end of the automated demonstration, a new tab appears; examinees for whom keyboard/mouse events were detected are automatically added to this tab.