This rule is designed to detect anomalous behavior in Office 365 email accounts, specifically when a user sends an email and immediately hard deletes it within a short time frame (one hour). Such actions can indicate that the email account may have been compromised by threat actors attempting to cover their tracks by removing forensic details of their activities. The detection mechanism utilizes an audit log to search for specific operations where an email was sent, followed by a hard delete operation, checking that these occurrences happened within a restricted time window. While there are legitimate reasons for users to perform these actions, they may not conform to best practices, leading to potential false positives if a user regularly cleans their mailbox.