texas a&m , galveston professor irwin horwitz sent an email to his strategic management class telling the approximately-30-person class would all fail .
in the email he said he witnessed cheating , false rumors and bad behavior .
he said in his 20 years of teaching he had never failed a class and rarely failed students .
the university administration has said that the failing grades will not hold .
department head is taking over horowitz 's class and students will be graded solely on academics .