Original sentence: The incident began with the death of four ATF Special Agents and ended with the deaths of 76 people, including 23 children (it remains unclear the extent to which these deaths may have been by suicide, or otherwise caused by actions of those within the compound)
Edited sentence: The incident which began with the murder of four ATF Special Agents and ended with the deaths of 76 people, including 23 children (it remains unclear the extent to which these deaths may have been by suicide, or otherwise caused by actions of those within the compound)