Gunfire rang out at an office building near NRG Stadium Wednesday.

A man who apparently had mental health issues was killed after witnesses said he became violent, HPD officers said.

No one else was injured.

It happened on the fifth floor of the Community Health Choice building at 2636 South Loop.

Police say the dead man had an appointment with a counselor at a center for people with mental disabilities. The staff decided to reschedule because he said he wasn't feeling well. The man left and came back within half an hour and had a "mental episode," according to police.

Surveillance video: Shooting scene inside office building

“Yelling, making demands, kicking on the doors, kicked in the glass door, totally damaged," said HPD Detective Willis Huff. "Probably a frightening situation for many.”

The staff, mostly women, felt threatened so they locked the doors. That's when the man went next door to a tax consulting business. The owner of the business fired one shot at the man and killed him, police said. The man's attorney said the victim lunged at his client and he felt threatened.

Carla Wilkerson was at a doctor's office on the first floor when she learned about the shooting.

"It was scary to me, it was. I was nervous but we locked the doors," Wilkerson said. "We didn't move until someone told us we could."

Wilkerson's granddaughter works on the 9th floor of the building. She texted Wilkerson to let her know she was OK.

A sign is posted saying "Open carry" is allowed in the building. The shooter had a license to carry, according to police. So far, no charges have been filed in the case.

The dead man's name has not been released. Police say it didn't appear that he was armed.