PITTSBURGH (KDKA) — Just who would enter a psychiatric hospital with two semi-automatic handguns and go on a shooting rampage?

Officials still don’t know.

“We do not know any of that information,” Pittsburgh Mayor Luke Ravenstahl said. “It is still being investigated.”

Police sources are telling KDKA that the shooter had no identification on his person — and that they are now taking his fingerprints to run through databases to try to determine his identity.

Western Psych President Claudia Roth says it is not known whether he is a former patient.

“I have no knowledge of who the shooter was,” she said.

While it is not clear what relationship the gunman had with Western Psych, in recent years three people who were treated or had some evaluation from the institute were charged and then later convicted of murder.

Andrea Curry Demus, Terrence Andrews and Troy Hill each had a history of mental illness and were charged in senseless killings.

In the wake of those killings, in 2008 the state Department of Public Welfare put a moratorium on Western Psych, suspending for a time its ability to take on more out-patients.

And Thursday as employees kept a vigil outside of the institute, nurse Julia Jackson said there have long been fears regarding safety.

“There’s always been fears and always been talk that something like this is going to happen,” she said. “We’re definitely all very scared to go back to work.”

Security guards at the institute are not armed and at a press conference Roth said the institute would conduct a review of its security.

“Safety and security is of our utmost concern for our patients, our visitors and our staff and that will continue to be at the fore,” she said.

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