toms cut off at two inches

I have had three plantings of two plants each in the same small raised bed cut off and dragged to a sheltered corner of the bed. All six plants have been about two feet tall and as far as I can see not much has been eaten. Emptied the entire bed this evening to see if anything was living there but found nothing.
 Anyone guess what my problem is and can I kill it with a stick?
 Taller beds with toms in are untouched.

beds inside greenhouse Learner so will not be wind, but with you on the mammal thing.Decided to try for the fourth time and surround plants with mousetraps.............land mines and small explosive charges crossed my mind but might count as over the top.