Slave revolt was always an undercurrent in this type of system. One way it was combated was through the activity of the secret service. This elite and covert organization consisted of warriors under the age of 30. They were charged with keeping any revolt talk or action in check through whatever means necessary. This special op group would serve for two years. They frequently roamed at night and killed any helot found out of doors. They could even strike during the day if the killing served as an example to others. For example the strongest slave could be targeted as they worked in the fields to emphasize the point they were to only do what they were told to do or else. Again the military might and aggressive thought process showed through.