We had an incident earlier in the week where data was accidentally deleted from a database and we needed to track down when it happened and who caused it. 

There are a few undocumented functions for reviewing the logs, 
https://www.sqlskills.com/blogs/paul/using-fn_dblog-fn_dump_dblog-and-restoring-with-stopbeforemark-to-an-lsn/

one of which is fn_dump_dblog, which can review data in a log file. However, since the Backup Pro logs are compressed and have a .sqb extension, is there any way, other than the slow and time consuming "backup file converter" utility? 

We were able to figure it out using a SQL monitor app (sorry, not SQL Monitor) to pin-point the time and user, then restore the log to a specific time to confirm it, but it would have been nice to use these undocumented function(s) instead.