DALLAS (AP) — An outdoor concert in Dallas where one person was killed and 15 others were wounded by gunfire over the weekend did not have a permit, police said Monday.

In addition to the people killed or wounded, a woman suffered a non-gun-related injury, police said. The victims ranged in age from 13 to 29 and were in stable condition, police Chief Eddie Garcia said during a Monday news conference.

Garcia said that with “a permit and proper promoter oversight, we can better be prepared for events and crowds.”

Seven Dallas police officers were approved to work the event off-duty, but that shouldn’t have happened since the event didn’t have a permit, Garcia said. They had all left by the time the shooting happened, he said.

“We’re looking at our internal policies to take a closer look at approvals for these types of jobs,” Garcia said.

Police said officers responded at about 12:13 a.m. on Sunday to the field in southwest Dallas where the concert was held. Garcia said that one person fired a gun into the air, then an argument broke out and another person fired in the crowd’s direction.

Near the concert stage, police found 26-year-old Kealon Dejuane Gilmore lying on the ground with a gunshot wound to the head. Gilmore died at the scene.

“People coming to an event should worry about enjoying themselves, not to have fear if won’t make it home,” García said.

The investigation is ongoing. A police spokeswoman said the organizers’ identities were not immediately available, so they could not be reached for comment.

Saturday night’s shooting happened two weeks after 10 people were shot on March 19 during a spring break party at a Dallas event venue.