Yesterday (June 1), at least four people, including the gunman, were killed after gunfire erupted inside a Tulsa, Oklahoma medical facility.

Tulsa police Capt. Richard Meulenberg told CNN, “It was just madness inside, with hundreds of rooms and hundreds of people trying to get out of the building.”

In a press conference held after the incident, Tulsa police Deputy Chief Eric Dalgleish revealed that just before 5 p.m. yesterday, officers received notice of a person with a gun at the Natalie Medical Building. The facility is a doctor’s office situated on the campus of Saint Francis Hospital.

The deputy chief shared that the responding officers who arrived within minutes “were hearing shots in the building, and that’s what directed them to the second floor.”

According to the police captain, the gunman was found dead inside the building. The suspect’s name has not been publicly released.

Reports state that the shooter died from self-inflicted gunshot wounds. Meulenberg believes there were two weapons used, a semiautomatic rifle and a semiautomatic pistol. Both firearms were discovered near the deceased suspect. Officials added that two victims were found in the same room as the gunman.

Dalgleish noted that it is unknown if those killed during the shooting were visitors, medical staff or patients.

“You can’t even go to a store, you can’t even go to school, now you can’t go to the doctor?” said Lachelle Nathan, who was taking her grandkids to a doctor’s appointment when the shooting occurred.

Yesterday’s events add to a growing number of recent mass shootings, including the May 14 racially motivated attack at a grocery store in Buffalo, New York. That tragedy was followed by the May 24 Uvalde, Texas mass shooting at Robb Elementary School.

Around 10 others suffered from non-life-threatening injuries in the Tulsa attack. No police were harmed during the incident.

“He very purposefully went to this location, went to a very specific floor, and shot with very specific purpose,” Meulenberg said of the gunman. “This was not a random shooting by this individual.”

Authorities are working to determine a motive.