The suspected gunman, 24-year-old Deion Patterson, has been charged with one count of murder and four counts of aggravated assault.

He waived his Thursday court appearance, according to Atlanta ABC affiliate WSB.

The suspected gunman, 24-year-old Deion Patterson, was armed with a semi-automatic handgun when he allegedly shot five people in a medical center waiting room, according to court documents.

The documents identify the surviving victims as Georgette Whitlow, Lisa Glynn, Jazzmin Daniel and Alesha Hollinger. All four of them remain hospitalized.

Hollinger was shot in the face, according to the documents, while Daniel was shot multiple times in the abdomen. Whitlow was shot in the arm and Glynn was shot in the abdomen.

Amy St. Pierre, 39, an employee of the Centers for Disease Control and Prevention, was killed in Wednesday's shooting.

Atlanta Mayor Andre Dickens released an impassioned letter addressed to city residents on Thursday pleading for change in the wake of Wednesday's mass shooting in a medical center waiting room.

"This suspect was arrested and will stand trial for his crimes," the mayor said. "But that doesn’t change the fact that one woman died, and four others were seriously injured. It doesn’t change the fact that our city experienced a collective trauma. Families are grieving today, and our community is on edge."

"We will learn more in the coming days about the circumstances of this shooting. But one thing we already know is that an incident like this is tragically too common in America," Dickens said. "We need national action to change the way we treat mental health. And we need action that keeps guns out of the hands of people who should not have them."

"We cannot accept mass shootings as normal in our country," he continued. "Other nations have challenges with mental health, but they don’t have this level of gun violence that we do."

"It’s the guns," the mayor stressed. "While we respect the rights conveyed by the 2nd Amendment, we also need more actions to protect the rights of our citizens to go about their lives -- to go to a doctor’s office, a supermarket, a gas station, their school -- without the threat of being gunned down."

The Centers for Disease Control and Prevention confirmed the 39-year-old victim who was killed in Wednesday's shooting as Amy St. Pierre.

"CDC is deeply saddened by the unexpected loss of a colleague killed today in the Midtown Atlanta shooting," it said in a statement. "Our hearts are with her family, friends and colleagues as they remember her and grieve this tragic loss."

-ABC News' Jason Volack

Three of the four women who were shot and injured remain in the intensive care unit, Dr. Robert Jansen, the chief medical officer at Grady Health, said at a news conference Thursday.

Two of those three women are "critical" and will return to the operating room for additional procedures, he said. The third patient in intensive care is stable and hopefully can move out of the ICU later in the day, he said.

The fourth woman who was shot is in stable condition, he said.

"As of right now everybody is as stable as they can be given the nature of their injuries," Jansen said.

Jansen said he's spoken with two of the injured victims.

"They have been traumatized," he said.

"They are very grateful for the support and care they've received," he said, however, "the fact that they were in a health care facility just makes it worse."

Jansen noted that "the impact" of this shooting "on the staff is something you can't imagine."

"Unfortunately, in this day and age, seeing shooting victims is almost a daily occurrence here," he said.

"But when they come in like this, particularly because it happened in a health care setting, it resonates more," he said, adding that the hospital staff is being offered support.