Investigators will enlist the help of psychological experts to craft a profile of John Shick with the hope of understanding why he shot six people, killing one, inside Western Psychiatric Institute and Clinic.
Knowing his motives -- and whether there were warning signs -- could help prevent similar attacks in the future.
Law enforcement officials on Thursday said they had spoken to the 30-year-old Mr. Shick's parents, had seen some of his medical records and were still sorting through ample evidence collected from his North Oakland apartment to learn more about him and his mental health history.
"There's a lot of evidence that, from a layperson's perspective, we don't completely understand," District Attorney Stephen A. Zappala Jr. said after meeting with Pittsburgh police detectives about the case. He said psychologists and psychiatrists will help investigators decipher the items -- including handwritten messages in notebooks and on walls, bottles and wicks investigators think were the makings of Molotov cocktails, and a printed brochure, apparently available to the public, providing Western Psych's floor plans.
Covering a table in Mr. Shick's apartment were at least 43 prescription medications to fight ailments such as depression, anxiety, migraines, seizures, chronic kidney disease, impotence, high cholesterol, high blood pressure, intestinal worms, gastric reflux, ulcers, gallbladder trouble, irritable bowel syndrome and chronic pancreatitis. There were caffeine pills, sedatives, hypothyroid drugs, narcotic painkillers and drugs to treat Hodgkin's disease.
Sources said many of the pills were self-prescribed from online pharmacies overseas. Among Mr. Shick's rambling messages were handwritten complaints about his medical treatment for a variety of physical ailments, sources said. The notations included complaints about various doctors and what Mr. Shick characterized as their misdiagnoses of his ailments. Mr. Shick was particularly upset with a UPMC internal medicine physician who appeared to have treated him in the past. The doctor lived in the same apartment building.
From Mr. Shick's apartment alone, there was enough evidence to stretch across an entire wall of a large conference room at Pittsburgh police headquarters, Mr. Zappala said.
Yet only a fractured portrait of Mr. Shick as a gifted yet troubled former grad student has emerged in the week since the shootings. UPMC employees marked the day with two minutes of "silence and reflection" at 2 p.m. Thursday. Of the five people wounded during the violence, four remained at UPMC Presbyterian on Thursday, where all were listed in fair or good condition. One man was expected to be discharged soon.
Michael Schaab, 25, a therapist who worked with elderly patients at Western Psych, was fatally shot in the building's lobby. Mr. Shick was shot to death during a gun battle with University of Pittsburgh police officers. Police have said Mr. Shick fired with two 9 mm handguns, pausing at least once to reload.
A week after the rampage, a Western Psych employee, who asked to remain anonymous, said the sentiment among the hospital's employees is the same: "We want to know what happened. We want to know, why did he do it? What doctor was he after? Was there something that could have prevented it?"
But UPMC has not been forthcoming with information, the employee said, and "that makes it an uneasy feeling because it leaves a lot open to speculation."
Pittsburgh police and city officials have refused to discuss the details of the case or answer questions about what contact police agencies might have had with Mr. Shick prior to the violence, whether he had made threats against UPMC in the past, whether he was targeting a specific doctor or how he obtained the guns.
"We may never know the answers to a lot of questions that people may have," the city's Public Safety Director Michael Huss said Thursday. "It's a very unfortunate situation. We still continue to investigate the details around it."
Mr. Zappala said city police detectives have been in contact with Mr. Shick's parents, Susan and Larry Shick, who have been sailing in the Caribbean. Mr. Zappala did not know their plans for their son's body.
They have been cooperative with authorities.
"They said, whatever you need, we'll help you out with it," Mr. Zappala said, declining to describe their reaction to news of the shooting because he had not spoken to them. "My read is that it's a very, very difficult process for them."
A look at Mr. Shick's medical records from UPMC Presbyterian showed that doctors there had expressed concerns about his mental state, Mr. Zappala said, declining to elaborate. He said police had not been able to study records from Western Psych because UPMC would not release them without a court order.
The hospital system allowed a subpoena to suffice for Mr. Shick's medical records sought from UPMC Presbyterian.
Allegheny County Orphans' Court Judge Lester G. Nauhaus on Tuesday signed an order for UPMC to comply with a subpoena from the medical examiner's office. He added a handwritten notation: "The content of the records [sic] are not to be shared with any person or entity without further order of court."
He said Thursday he added the language because he did not want the office to have "carte blanche to get the records and then publish them."
The district attorney's office is also investigating the shooting of Mr. Shick by three University of Pittsburgh police officers. Their findings confirmed that the officers did not hit Mr. Schaab.
Michael A. Fuoco, Sean Hamill and Jonathan D. Silver contributed.