There is a new set of challenges in Fortnite – The Spire. You get these jobs from Tarana in Boney Burbs. One of the new quests requires you to find the Thief and play the Last Audio Log.
Find the Thief and Play the Last Log challenges. – The Spire
Find The Thief & Play the last Log
Raz is the thief and you need to speak to him at Colossal Crops. Ask him about “The Spire” and he will tell you that you need to find an audio log. There is a tree on a ruined wall right next to the building where Raz is located. Interact with the final log to play the audio to complete the challenge.