Beset with anxiety and depression, Deion Patterson was desperate.

The 24-year-old Coast Guard veteran asked the Atlanta VA Medical Center to prescribe Ativan, an effective but addictive anti-anxiety medication. When the VA refused, Patterson made an appointment with a doctor in Midtown Atlanta. His mother would accompany him.

But they arrived late for the appointment Wednesday. Told he couldn’t see the doctor, Patterson drew a semiautomatic handgun from his brown satchel and opened fire in the waiting room of Laureate Medical Group, the police said.

He shot another patient, Amy St. Pierre, point-blank in the head, a witness said. The 38-year-old mother of two, who worked for the Centers for Disease Control and Prevention, died instantly.

Patterson shot four other women — two employees of the medical practice and two patients waiting to see doctors — before fleeing from the Northside Hospital Midtown medical office building, the police said. Officers captured him eight hours later in suburban Cobb County, concluding an episode that stirred fear across metro Atlanta.

A day later, answers to basic questions remained elusive. Where did the shooter acquire his weapon? Why did he turn his rage on innocent bystanders? How did he elude a massive manhunt for so long? Could the shooting have been averted if he had received the treatment he sought?

The Department of Veterans Affairs is investigating whether gaps in care contributed to the rampage, a person knowledgeable about departmental discussions told The Atlanta Journal-Constitution. The person was not authorized to speak on the record.

Meanwhile, the Atlanta police are trying to piece together a timeline of events that preceded and followed the shooting.

Patterson’s weapon is of particular interest, Chief Darin Schierbaum told The Atlanta Journal-Constitution on Thursday: “where it came from, how he came to be in possession of it, whether he possessed it legally.”

The police also are examining surveillance video from Atlanta and Cobb County, hoping to recreate Patterson’s escape from the crime scene. Detectives determined that he ran from the medical building to a nearby gas station, where he stole a pickup truck that had been left unattended with the engine running. Surveillance devices recorded him driving the truck into Cobb County about 30 minutes after the shooting, and officers found the vehicle two hours later in a parking garage near Truist Park.

Schierbaum said Patterson, who had apparently made no previous threats of violence, is not believed to have accosted anyone in the hours between the shootings and his capture.

Authorities charged Patterson with felony murder and four counts of aggravated assault. He waived his first appearance before a judge Thursday morning and is housed in a medical observation unit at the Fulton County Jail.

Patterson is “a veteran and suffers from apparent mental health issues,” his public defender, Shawn Hoover, said in a statement. “My team is investigating the details and circumstances of the charges to provide him with zealous, effective and timely representation.”

St. Pierre’s family described her as their “social conscience” and “a generous supporter of worthy causes.”

“Our beloved Amy was brilliant, kind, big-hearted and simply the ‘best of the best,’” the family said in a statement.

Court records identified the surviving victims as Lisa Glynn, who was shot in the abdomen; Jazzmin Daniel, who suffered multiple abdominal wounds; Alesha Hollinger, who was shot in the face; and Georgette Whitlow, who was shot in the arm.

Two of the women remained in critical condition at Grady Memorial Hospital and underwent additional surgery Thursday, said Dr. Robert Jansen, the facility’s chief medical officer.

Meanwhile, details began to emerge Thursday about Patterson’s history of mental illness.

He had been received psychiatric treatment from the VA since March, the Journal-Constitution learned. He missed an appointment in April but showed up for another meeting on April 27. His mother, Minyone Patterson, accompanied him to that appointment and asked doctors to give her son an Ativan prescription.

The mother told The Associated Press that the VA denied her son the Ativan even though she promised to make sure he took the proper dosage.

A VA doctor prescribed Patterson a different anti-anxiety drug, his mother said, and he had had “some mental instability going on” since he began taking the medication on Friday. By the time they arrived at the appointment in Midtown on Wednesday, she said, Patterson had experienced a “mental break.”

Minyone Patterson broke into tears as she spoke of the shooting victims, the AP reported.

“Those families, those families,” she said. “They’re hurting because they wouldn’t give my son his damn Ativan. Those families lost their loved ones because he had a mental break because they wouldn’t listen to me.”

(Staff writers Katharine Landergan, Alexis Stevens, Rosana Hughes, Caroline Silva, Mirtha Donastorg, Johnny Edwards, and Shaddi Abusaid contributed reporting.)

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