Scan for the wraith Edit
Use the proximity indicator to locate the cloaked wraith. Once you've scanned it, the sniper will kill it with one shot. At the Pathfinder's request, the "mystery sniper" will reveal himself and allow you to approach him at the nearby sentry point.
Find the sniper Edit
Go and have a conversation with Orev to complete the task.
If you ask him about joining the Resistance, you can convince him if Jaal is in the squad.
The name "White Death" is an allusion to the Finnish sniper Simo Häyhä, who was nicknamed White Death by Soviet soldiers. Häyhä amassed a body count of over 500 during the course of the Winter War.