Currently, there isn't a direct method to identify who closed a specific task. You might infer the responsible party by comparing the notes on the task with those in the job audit trail. However, this doesn't ensure that the person who left notes on both is the one who closed the task. Other customers have also expressed interest in this feature, termed "Task Management Audit Trail." I strongly suggest reviewing the idea and casting your vote. Here's the Link for your convenience.
Jaouad S.
Customer Support Advocate II
