frontier airlines referred all questions to the cleaning company .
they say the three men work for a company that cleans planes for frontier airlines , but their names were n't released .
walker said a third man then got involved and after some shoves , he pulled out a knife and stabbed one of the man in the thigh .
the third worker soon confronted by police said .
the stabbing happened around 11 a.m. in a break room for worldwide flight services , an airplane cleaning contractor for frontier airlines , in terminal e. philadelphia police lt .
police say one man turned out a light , angering another worker .
an argument over a light switch escalated into a deadly stabbing thursday morning at philadelphia international airport , police said .
philadelphia ( ap ) — authorities say an argument over a break room light led to a deadly stabbing involving three workers at philadelphia international airport .
the stabbing occurred around 11:30 a.m. thursday near gate e6 in what city police say was a " secure area . "