Southern Illinois University police are investigating an altercation that broke out on Friday night.  Campus spokesperson Rae Goldsmith told WSIL-TV that there were reports of shots fired near a talent show at Lawson Hall, but there was no evidence of gunfire.  Students in the nearby COM building reportedly locked themselves in the building until the situation was cleared up.  SIU police searched all nearby buildings before designating the area secure and the campus fully open.