Baton Rouge police arrested one man Friday and continued searching for a second gunman in a Thursday night shooting that wounded two people outside of an Istrouma High School sporting event that marked the first game under the lights of the new field.

An argument started in the bleachers during a junior varsity spring football game and continued out into Winbourne Avenue and parking lot as the game ended around 8:40 p.m., said Sgt. L'Jean McKneely, a Baton Rouge police spokesman. Two people pulled out guns and shot at a third man on Winbourne Avenue near the front of the school.

The man hid behind a vehicle, but a stray bullet struck a pregnant female bystander who was on the other side of the parking lot, according to an arrest report. A 14-year-old girl was also grazed by a bullet, McKneely said. The pregnant woman is expected to survive her injuries, but the status of her unborn baby is unknown, McKneely said. 

Investigators determined that 19-year-old Nortrell Poole was one of the shooters and arrested him on attempted second-degree murder, attempted second-degree feticide and aggravated criminal damage to property. Police found spent cartridge casings from two different caliber weapons at the scene. They have not identified the second shooter.

Poole fled the scene of the shooting in a beige Nissan Maxima, but abandoned it on Dutton Avenue, according to his arrest report.

Poole is not a student at Istrouma High School, said Taylor Gast, an East Baton Rouge Parish school system spokeswoman, on Friday. Gast said it does not appear that those involved in the shooting were students, but the case is still under police investigation.

While police continue to investigate the incident, East Baton Rouge School Superintendent Warren Drake said the district will increase security measures at future games, including a larger law enforcement presence and the possibility of metal detectors at the gates to sporting events.

"We are heartbroken for those two people who were wounded," Drake said. "We’re going to make sure that we have all security measures in place so this doesn’t happen again."

There were three East Baton Rouge Parish Sheriff's Office deputies working extra duty at the Thursday night game, but the school system will increase that number for all future spring football games. Drake said he wants at least eight officers at each game in the fall when the crowds will be larger than the spring games. While school officials will evaluate security at all home fields, Drake said he is specifically looking at higher fences and more lighting at Istrouma High School.

"This school has been a bright spot in 70805, and we have seen the revitalization of that area of town since that school opened," Drake said. "I hate to see where someone thinks they can come in and ruin what we have going there even though it happened out on Winbourne. I'm not going to let the bad guys take over that school and that area."

The investigation remains ongoing, McKneely said. He asked anyone with information to contact the Violent Crimes Unit (225) 389-4869 or Crime Stoppers at (225) 344-7867. 

Follow Emma Discher on Twitter, @EmmaDischer.