Jason Kelce's altercation with an unruly spectator at the Penn State game this weekend is on law enforcement's radar ... with officials looking into the matter.
TMZ Sports has learned ... the school's Police and Public Safety agencies are investigating the viral interaction between the Philadelphia Eagles legend and a man who referred to his brother, Travis, as a homophobic slur ... and the process is "ongoing."
Kelce was in town to catch the massive showdown between Ohio State and Penn State .