CARROLLTON, Texas -- A junior varsity football game at Hebron High School stadium abruptly ended when a shooting broke out between two men Thursday night.

Police said no students were involved and authorities were able to clear and secure the stadium.

The team was playing against Irving's Nimitz High School when they began fighting at the stadium off Plano Parkway during the third quarter of the game.

Witnesses called 911 to report the fighting in the stands. The two men decided to take the argument outside of the stands and went as far as the ticket booth when one of them pulled out a gun and shot the other, police said.

Responding officers took the shooter, a 47-year-old Carrollton man into custody, but later released him without charges, because detectives believe he was acting in self defense. The case will go to a grand jury, which will make the final decision on whether there should

Carrollton Fire Rescue transported the 31-year-old Fort Worth man who was shot to Texas Health Presbyterian Hospital of Plano where he remained in critical condition Friday.

Police are not releasing their names. at this time.

Lewisville ISD had increased security presence at Hebron High School Friday, and is reviewing security measures for future football games.

A referee was treated for chest pains in the moments after the shooting, but no one else was hurt. Detectives are interviewing the shooter and several witnesses and are working to carefully gather all the facts and evidence.

Police say they don't feel there is any danger to students but as a safety precaution, additional officers will be on campus Friday.

This is a developing story and we will be continuously updating throughout. Check back for new information and don't forget to download our free WFAA app to stay up-to-date on all news stories in the Dallas-Fort Worth area.